62 resultados para Modification of the microflora


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Unexpected nonadditivity of currents encountered in the electrochemistry of mixtures of ferrocene (Fc) and cobaltocenium cation (Cc+) as the PF6 - salt has been investigated by direct current (dc) and Fourier-transformed alternating current (ac) cyclic voltammetry in two aprotic (1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate) and three protic (triethylammonium formate, bis(2-hydroxyethyl)ammonium acetate, and triethylammonium acetate) ionic liquids (ILs). The voltammetry of the individual Fc0/+ and Cc+/0 couples always exhibits near-Nernstian behavior at glassy carbon and gold electrodes. As expected for an ideal process, the reversible formal potentials and diffusion coefficients at 23 ( 1 °C in each IL determined from measurement on individual Fc and Cc+ solutions were found to be independent of electrode material, concentration, and technique used for the measurement. However, when Fc and Cc+ were simultaneously present, the dc and ac peak currents per unit concentration for the Fc0/+ and Cc+/0 processes were found to be significantly enhanced in both aprotic and protic ILs. Thus, the apparent diffusion coefficient values calculated for Fc and Cc+ were respectively found to be about 25 and 35% larger than those determined individually in the aprotic ILs. A similar change in the Fc0/+ mass transport characteristics was observed upon addition of tetrabutylammonium hexafluorophosphate (Bu4NPF6), and the double layer capacitance also varied in distinctly different ways when Fc and Cc+ were present individually or in mixtures. Importantly, the nonadditivity of Faradaic current is not associated with a change in viscosity or from electron exchange as found when some solutes are added to ILs. The observation that the 1H NMR T1 relaxation times for the proton resonance in Cc+ also are modified in mixed systems implies that specific interaction with aggregates of the constituent IL ionic species giving rise to subtle structural changes plays an important role in modifying the mass transport, double layer characteristics, and dynamics when solutes of interest in this study are added to ILs. Analogous voltammetric changes were not observed in studies in organic solvent media containing 0.1 M added supporting electrolyte. Implications of the nonadditivity of Faradaic and capacitance terms in ILs are considered.

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The modification of denial, defensiveness, and cognitive distortions and the enhancement of victim empathy are central components in the treatment of pedophilic sex offenders (PSOs) and are thus important factors to evaluate. This review of the literature highlights three broad problems with self-report measures of these variables. First, the psychometric properties of measures vary enormously, with some having no established validity or reliability. Second, the purpose of the measure is generally quite transparent, enabling the respondent to easily pick the socially acceptable responses. Finally, it is difficult to determine which are the best measures to use in assessing PSOs. Measures range from those designed for the general public to those designed specifically for PSOs. Also, they range from those that assess broad processes (e.g., general empathy) to those that assess offensespecific variables (e.g., victim empathy). This article argues that these issues need to be addressed to improve both the assessment of these processes among PSOs and the evaluation of treatment programs for PSOs.

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The hydrolysis of (Me3SiCH2)PhSnCl2( 1) was studied under two different reaction conditions (i) by using an excess of aqueous NaOH in toluene at reflux temperature and (ii) by using small amounts of NEt3 and water in CH2Cl2 at room temperature. For (i) the products  (Me3SiCH2)Ph2SnOSnPh2(CH2SiMe3)( 2) and [(Me3SiCH2Sn)12O14(OH)6](OH)2( 3) were isolated indicating that a phenyl group migration took place. For (ii) the dimeric tetraorganodistannoxane [(Me3SiCH2)Ph(Cl)SnOSn(Cl)Ph(CH2SiMe3)]2( 4) was obtained. In solution, 4 exists as an equilibrium mixture of all five possible isomers 4a–4e; in the solid state two of these isomers 4d and 4e co-crystallized in the same crystal modification. The observation of interconvertible isomers of 4 was attributed to the kinetic lability of the ladder-like Sn4O2Cl4 structural motif. Compounds 1 and 4 were investigated by X-ray crystallography.

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In this study we examined the role of biopsychosocial factors on adolescent boys' body modification strategies over an 8-month period. Participants were 434 adolescent boys aged between 11 and 16 years. The majority of respondents were from Anglo-Australian backgrounds (83%); the others were from Asian and European non-English-speaking backgrounds. The results indicated a consistent relationship between perceived encouragement to engage in body change strategies and increases in adolescents' body modification strategies, including muscle gain, weight gain, and weight loss. In addition, poor parent relations, being younger, and higher scores on the pubertal development scale predicted increased use of food supplements. However, the stability of the body modification strategies and the examined variables over the 8-month period were low. Further studies are needed to examine the stability of adolescent self-perceptions over both longer and shorter periods. Moreover, researchers need to include other factors that may be more relevant for adolescent boys (e.g., involvement in sports).

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Overweight and obesity has doubled among children in Australia. There is an urgent need to develop primary prevention strategies to prevent current and future unhealthy weight gain. The aims of this paper are to describe a randomized controlled trial (‘Switch-Play’) developed to prevent unhealthy weight gain among 10-year-old children and to report the findings of the process evaluation. Children from three government primary schools were randomized by class to one of four conditions: a behavioural modification group (BM; n = 69); a fundamental motor skills group (FMS; n = 73); a combined BM and FMS group (n = 90); or a control (usual classroom lessons) group (n = 61). Children in the BM group participated in 19 sessions that encouraged them to reduce screen-based behaviours, and identified physical activity alternatives. The FMS group participated in 19 lessons that focused on mastery of six skills: run, throw, dodge, strike, vertical jump and kick. The combined group participated in all the BM and FMS activities. The intervention specialist teacher reported that the children showed high enjoyment and engagement (88% lessons attended) in most aspects of the programme. At-home tasks were completed by 57–62% of the children, and 92% completed the in-class tasks. Two-thirds of the children in the BM group participated in the behavioural contracting to switch off the TV. Most of the children reported high enjoyment of the programmes, and only a small proportion (7–17%) reported difficulties in switching off their nominated TV shows. More than half the children reported reducing their TV viewing; however, less than half reported increasing their physical activity. It was found that most aspects of the intervention arms of the programme were successfully delivered to the majority of children participating in ‘Switch-Play’; that the programmes were delivered as intended; and that the programmes were favourably evaluated by participating children and their parents.

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The dynamics of fatty acid composition modifications were examined in tissues of Murray cod fed diets containing fish oil (FO), canola oil (CO) and linseed oil (LO) for a 25-week period and subsequently transferred to a FO (finishing/wash-out) diet for a further 16 weeks. At the commencement of the wash-out period, following 25 weeks of vegetable oil substitution diets, the fatty acid compositions of Murray cod fillets were reflective of the respective diets. After transfer to the FO diet, differences decreased in quantity and in numerousness, resulting in a revert to the FO fatty acid composition. Changes in percentages of the fatty acids and total accumulation in the fillet could be described by exponential equations and demonstrated that major modifications occurred in the first days of the finishing period. A dilution model was tested to predict fatty acid composition. In spite of a general reliability of the model (Y=0.9234X+0.4260, R2=0.957, P<0.001, where X is the predicted percentage of fatty acid; Y the observed percentage of fatty acid), in some instances the regression comparing observed and predicted values was markedly different from the line of equity, indicating that the rate of change was higher than predicted (i.e. Y=0.4205X+1.191, R2=0.974, P<0.001, where X is the predicted percentage of α-linolenic acid; Y the observed percentage of α-linolenic acid). Ultimately, using the coefficient of distance (D), it was shown that the fatty acid composition of fish previously fed the vegetable oil diets returned to the average variability of the fillet fatty acid composition of Murray cod after 70 or 97 days (LO and CO respectively).

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Wool fiber was modified by steam explosion in this study. SEM results show that some scales on the fiber surface were cleaved and tiny grooves generated during the explosion. FTIR results suggest no evident changes in the chemical composition of the fiber after the explosion treatment. However, the crystallinity of the fiber decreased slightly as the steam pressure increased based on the X-ray results. In the thermal analysis, DSC results show that the temperature corresponding to vaporization of absorbed water and cleavage of disulfide bonds respectively decreased as the steam pressure increased. The reduction in thermal decomposition energy of the treated fiber indicates that steam explosion might have destroyed some crystals and crosslinks of macromolecular chains in the fiber. The treatment also led to some alterations of the fiber properties, including reduction in strength, moisture regain and solubility in caustic solution.

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Habitat loss and modification is a major factor driving reductions of seabird populations. The white-faced storm petrel (Pelagodroma marina) is restricted to three breeding colonies within Victoria: Mud Islands and South Channel Fort in Port Phillip Bay, and Tullaberga Island off Mallacoota. The numbers of storm petrels breeding on Mud Islands and South Channel Fort have declined considerably, possibly a result of the significant vegetation changes, together with increases in local populations of other species of birds, most notably, silver gulls (Larus novaehollandiae). On Mud Islands the breeding area available to the storm petrels appears to be limited by the recent arrival of the Australian white ibis (Threskoirnis molucca), and straw-necked ibis (T. spinicollis) which now breed on the islands in large numbers (approximately 15,000 pairs). The impact of these changes on the storm petrels is poorly understood. The current status of storm petrels at Tullaberga Island is unknown. This study estimated the size of the breeding population at all three sites by determining burrow densities, and a burrow-scope was used to determine occupancy. Burrow density was found to be related to vegetation type and other habitat factors. This study has highlighted important information on the breeding habitat of the white-faced storm petrel and the implications for management are discussed.

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The modification of glassy carbon electrodes with random dispersions of nanotubes is currently the most popular approach to the preparation of carbon nanotube modified electrodes. The performance of glassy carbon electrodes modified with a random dispersion of bamboo type carbon nanotubes was compared with single walled carbon nanotubes modified glassy carbon electrodes and bare glassy carbon electrodes. The electrochemical performance of all three types for electrode were compared by investigating the electrochemistry with solution species and the oxidation of guanine and adenine bases of surface adsorbed DNA. The presence of edge planes of graphene at regular intervals along the walls of the bamboo nanotubes resulted in superior electrochemical performance relative to SWNT modified electrodes from two aspects. Firstly, with solution species the peak separation of the oxidation and reduction waves were smaller indicating more rapid rates of electron transfer. Secondly, a greater number of electroactive sites along the walls of the bamboo-carbon nanotubes (BCNTs) resulted in larger current signals and a broader dynamic range for the oxidation of DNA bases.

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Aims: The Polymeal was first proposed as a 'tastier and safer' alternative to a polypharmacy approach to cardiovascular disease risk reduction. The present study aimed to examine the affordability of the Polymeal, and to propose modifications based on economic considerations, and the latest scientific evidence, to achieve consistency with current public health recommendations.

Methods: Prices for each food component specified in the Polymeal were obtained from a major and independent supermarket chain in a representative middle socioeconomic demographic region of metropolitan Melbourne, Australia. Items included fish (114 g, four times/week), fruits and vegetables (400 g/day), dark chocolate (100 g/day), garlic (2.7 g/day), almonds (68 g/day) and red wine (150 mL/day). Prices were calculated using an average of the major brands, or the most commonly eaten fruits, vegetables or fish. Modifications of the Polymeal were proposed based on published research and public health recommendations since the Polymeal was first proposed.

Results: Average price of the Polymeal was AU$11.89 per day falling to AU$8.46 if the cheapest food items were chosen. Modifications to the Polymeal included: consuming fish oil capsules instead of fish, reduction in the quantity of dark chocolate and removal of red wine. These modifications halved the cost of the Polymeal, while choosing the cheapest food items further lowered the cost to AU$3.49 per day. Modification of the Polymeal gave substantial reductions in both energy and saturated fat (51% and 84%, respectively).

Conclusion: The modified Polymeal is a more affordable variation of the Polymeal, which takes into account current scientific evidence and public health recommendations.

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Purpose : Over the past two decades, the transtheoretical model (TTM) of change has become perhaps the most widely used model of behaviour change in the treatment of addictive and/or problem behaviours. More recently, the stages of change component of the TTM has been adopted for use in forensic settings. This paper aims to review the application of the TTM model to offender populations.

Arguments : The application of the TTM to offenders raises a number of issues regarding the process of behaviour change for offenders attending treatment programmes. It is argued that while the TTM has been designed to account for high frequency behaviour (e.g. smoking, alcohol misuse), offending behaviour may be less frequent and the process of change less cyclical. Moreover, it is suggested that the most important issue in a treatment context is the proper integration of the TTM constructs. There have been few empirical tests of this aspect of the model.

Conclusion :
While the TTM may have some value in explaining how rehabilitation programmes help offenders to change their behaviour, the stages of change construct is, by itself, unlikely to adequately explain the process by which offenders desist from offending.

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The White-browed Treecreeper Climacteris affinis is one of many woodland-dependent birds that are at risk from the encroachment of human-dominated land-uses into natural landscapes. The White-browed Treecreeper inhabits semi-arid woodlands in north-west Victoria, Australia, a vegetation community that has undergone extreme modification in the last century due to the expansion of agriculture in the region. Extant woodlands represent only 10% of the original woodland cover in the region, and are highly fragmented and disturbed in many districts. Thus, the survival of the White-browed Treecreeper may depend on active management. However, current knowledge of the ecology and biology of this species is virtually non-existent, and inadequate for informed and effective conservation actions. The aim of this thesis is to redress this situation and provide the ecological basis for sound conservation management of the species. The thesis consists of two parts: an investigation of habitat use at three spatial scales and a study of the social organization, nesting requirements, breeding behaviour and reproductive success of a population of White-browed Treecreepers. Fifty-six patches of remnant woodland in north-west Victoria were surveyed to determine the factors affecting the occurrence of the White-browed Treecreeper at the regional scale. It was detected in 16 patches, and was largely confined to two core districts - Yarrara and, Wyperfeld (Pine Plains). The floristic composition of the dominant tree species was an important determinant of patch occupancy, with the results providing quantitative support for the previously suspected affinity for Belah Casuarina pauper and Slender Cypress-pine Callitris gracilis — Buloke Allocasuarina luehmannii woodlands. However, the absence of the White-browed Treecreeper from several districts was due to factors other than a lack of appropriate habitat. Demographic isolation - the distance from the focal patch to the nearest population of the White-browed Treecreeper - was the most important variable in explaining variation in patch occupancy. Patches isolated from other treecreeper populations by more than 8.3 km in landscapes of non-preferred native vegetation, and 3 km in agricultural landscapes, were unlikely to support the White-browed Treecreeper. The impact of habitat loss and fragmentation on the capacity of individuals to move through the landscape (i.e. functional connectivity) is considered in relation to disruption to dispersal and migration, and the potential collapse of local metapopulations. Habitat use was then examined in a network of patches and linear strips of Belah woodland embedded in a predominantly cultivated landscape. A minimum area of 18.5 ha of Belah woodland was identified as the most important criterion for patch occupancy at the local scale. This landscape appeared to be permeable to movement by the White-browed Treecreeper, facilitated by the extensive network of linear habitat, and clusters of small to medium fragments. The third scale of habitat use investigated the frequency of use of 1-ha plots within tracts of occupied woodland. It is important to discriminate between habitat traits that operate at the population level, and those that act as proximate cues for habitat selection by individuals. Woodlands that have high tree density, extensive cover of low-stature shrubs, abundant lichen, a complex vertical structure, and relatively low cover of grass and herbs are likely to support larger populations of the White-browed Treecreeper. However, individuals appeared to be using tree dominance (positive) and tall shrub cover (negative) as proximate environmental stimuli for habitat selectivity. A relatively high cover of ground lichen, which probably reflects a ground layer with low disturbance and high structural complexity, was also a reliable indicator of habitat use. Predictive models were developed which could be used to plan vegetation management to enhance habitat for the White-browed Treecreeper. The results of the regional, landscape and patch-scale investigations emphasise that factors operating at multiple spatial scales influence the suitability of remnant vegetation as habitat for the White-browed Treecreeper. The White-browed Treecreeper is typical of many small Australian passerines in that it has high annual survival, small clutches, a long breeding season, multiple broods and relatively low reproductive rates. Reproductive effort is adjusted through the number of clutches laid rather than clutch size. They occupy relatively large, all-purpose territories throughout the year. However, unlike many group territorial birds, territory size was not related to the number of occupants. The White-browed Treecreeper nests in tree hollows. They select hollows with a southerly orientation where possible, and prefer hollows that were higher from the ground. At Yarrara, there was considerable spatial variation in hollow abundance that, in concert with territorial constraints, restricted the actual availability of hollows to less than the absolute abundance of hollows. Thus, the availability of suitable hollows may limit reproductive productivity in some territories, although the magnitude of this constraint on overall population growth is predicted to be small. However, lack of recruitment of hollow-bearing trees would increase the potential for hollow availability to limit population growth. This prospect is particularly relevant in grazed remnants and those outside the reserve system. Facultative cooperative breeding was confirmed, with groups formed through male philopatry. Consequently, natal dispersal is female-biased, although there was no skew in the sex ratio of the fledglings or the general adult population. Helpers were observed performing all activities associated with parenting except copulation and brooding. Cooperatively breeding groups enjoyed higher fledgling productivity than simple pairs, after statistically accounting for territory and parental quality. However, the difference reflected increased productivity in the 1999-breeding season only, when climatic conditions were more favourable than in 1998. Breeding commenced earlier in 1999, and all breeding units were more likely to attempt a second brood. However, only breeders with helpers were successful in fledging second brood young, and it was this difference that accounted for the overall discrepancy in productivity. The key mechanism for increased success in cooperative groups was a reduction hi the interval between first and second broods, facilitated by compensatory reductions in the level of care to the first brood. Thus, females with helpers probably achieved significant energetic savings during this period, which enabled them to re-lay sooner. Furthermore, they were able to recommence nesting when the fledglings from the first brood were younger because there were more adults to feed the dependent juveniles. The current utility, and possible evolutionary pathways, of cooperative breeding is examined from the perspective of both breeders and helpers. Breeders benefit through enhanced fledgling productivity in good breeding conditions and a reduction in the burden of parental care, which may impart significant energetic savings. Further, breeders may facilitate philopatry as a means for ensuring a minimum level of reproductive success. Helpers benefit through an increase in their inclusive fitness in the absence of opportunities for independent breeding (i.e. ecological constraints) and access to breeding vacancies in the natal or adjacent territories (i.e. benefits of philopatry). However, the majority of breeding unit-years comprised unassisted breeders, which suggests that pairs are selectively favoured under certain environmental or demographic conditions.