59 resultados para Ecological half-life


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Riparian zones are a characteristic component of many landscapes throughout the world and increasingly are valued as key areas for biodiversity conservation. Their importance for bird communities has been well recognised in semi-arid environments and in modified landscapes where there is a marked contrast between riparian and adjacent non-riparian vegetation. The value of riparian zones in largely intact landscapes with continuous vegetation cover is less well understood. This research examined the importance of riparian habitats for avifauna conservation by investigating the ecological interactions contributing to the pattern of bird assemblages in riparian and adjacent non-riparian habitats. Specifically, the focus is on the bird assemblages of riparian zones and those of adjacent non-riparian vegetation types and the influence that associated differences in resource availabilities, habitat structure and conditions have on observed patterns. This study was conducted in the foothill forests of the Victorian Highlands, south-east Australia. Mixed-species eucalypt (genus Eucalyptus) forests dominate the vegetation of this region. Site selection was based on the occurrence of suitable riparian habitat interspersed within extensive, relatively undisturbed (i.e. no recent timber harvesting or fire events) forest mosaics. A series of 30 paired riparian and non-riparian sites were established among six stream systems in three forest areas (Bunyip State Park, Kinglake National Park and Marysville State Forest). Riparian sites were positioned alongside the stream and the non-riparian partner site was positioned on a facing slope at a distance of approximately 750 m. Bird surveys were carried out during 29 visits to each site between July 2001 and December 2002. Riparian sites were floristically distinct from non-riparian sites and had a more complex vegetation structure, including a mid-storey tree layer mostly absent from non-riparian sites, extensive fine litter and coarse woody debris, and dense ground-layer vegetation (e.g. sedges and ground ferns). The characteristic features of non-riparian habitats included a relatively dense canopy cover, a ground layer dominated by grasses and fine litter, and a high density of canopy-forming trees in the smaller size-classes. Riparian zones supported a significantly greater species richness, abundance and diversity of birds when compared to non-riparian habitats. The composition of bird assemblages differed significantly between riparian and non-riparian habitats, with riparian assemblages displaying a higher level of similarity among sites. The strongest contributors to observed dissimilarities between habitat types included species that occurred exclusively in either habitat type or species with large contrasts in abundance between habitat types. Much of the avifauna (36%) of the study area is composed of species that are common and widespread in south-east Australia (i.e. forest generalists). Riparian habitats were characterised by a suite of species more typical of wetter forest types in south-east Australia and many of these species had a restricted distribution in the forest mosaic. Some species (7%) occurred exclusively in riparian habitats (i.e. riparian selective species) while others (43%) were strongly linked to these habitats (i.e. riparian associated species). A smaller proportion of species occurred exclusively (2%) in non-riparian habitats (i.e. non-riparian selective species) or were strongly linked to these habitats (10%; i.e. non-riparian associated species). To examine the seasonal dynamics of assemblages, the variation through time in species richness, abundance and composition was compared between riparian and non-riparian sites. Riparian assemblages supported greater richness and abundance, and displayed less variation in these parameters, than non-riparian assemblages at all times. The species composition of riparian assemblages was distinct from non-riparian assemblages throughout the annual cycle. An influx of seasonal migrants elevated species richness and abundance in the forest landscape during spring and summer. The large-scale movement pattern (e.g. coastal migrant, inland migrant) adopted by migrating species was associated with their preference for riparian or non-riparian habitats in the landscape. Species which migrate north-south along the east coast of mainland Australia (i.e. coastal migrants) used riparian zones disproportionately; eight of eleven species were riparian associated species. Species which migrate north-south through inland Australia (i.e. inland migrants) were mostly associated with non-riparian habitats. The significant differences in the dynamics of community structure between riparian and non-riparian assemblages shows that there is a disproportionate use of riparian zones across the landscape and that they provide higher quality habitat for birds throughout the annual cycle. To examine the ecological mechanisms by which riparian assemblages are richer and support more individual birds, the number of ecological groups (foraging, nest-type and body mass groups) represented, and the species richness of these groups, was compared between riparian and non-riparian assemblages. The structurally complex vegetation and distinctive habitat features (e.g. aquatic environments, damp sheltered litter) provided in the riparian zone, resulted in the consistent addition of ecological groups to riparian assemblages (e.g. sheltered ground – invertebrates foraging group) compared with non-riparian assemblages. Greater species richness was accommodated in most foraging, nest-type and body mass groups in riparian than non-riparian assemblages. Riparian zones facilitated greater richness within ecological groups by providing conditions (i.e. more types of resources and greater abundance of resources) that promoted ecological segregation between ecologically similar species. For a set of commonly observed species, significant differences in their use of structural features, substrates and heights were registered between riparian and non-riparian habitats. The availability and dynamics of resources in riparian and non-riparian habitats were examined to determine if there is differential availability of particular resources, or in their temporal availability, throughout the annual cycle. Riparian zones supported more abundant and temporally reliable eucalypt flowering (i.e. nectar) than non-riparian habitats throughout the annual cycle. Riparian zones also supported an extensive loose bark resource (an important microhabitat for invertebrates) including more peeling bark and hanging bark throughout the year than at non-riparian sites. The productivity of eucalypts differed between habitat types, being higher in riparian zones at most times for all eucalypts combined, and for some species (e.g. Narrow-leaved Peppermint Eucalyptus radiata). Non-riparian habitats provided an abundant nectar resource (i.e. shrub flowering) at particular periods in the annual cycle. Birds showed clear relationships with the availability of specific food (i.e. nectar) and foraging resources (i.e. loose bark). The demonstration of a greater abundance of resources and higher primary productivity in riparian zones is consistent with the hypothesis that these linear strips that occupy only a small proportion of the landscape have a disproportionately high value for birds. Riparian zones in continuous eucalypt forest provide high quality habitats that contribute to the diversity of habitats and resources available to birds in the forest mosaic, with positive benefits for the landscape-level species pool. Despite riparian and non-riparian habitat supporting distinct assemblages of birds, strong linkages are maintained along the riparian-upslope gradient. Clearly, the maintenance of diverse and sustainable assemblages of birds in forest landscapes depends on complementary management of both riparian and non-riparian vegetation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Seventy nine prisoners completed a questionnaire before and after prison release. Drug use and health ratings changed over time, while employment and housing stability, finance, and social support did not. Participants had higher depression and anger before leaving prison, but anxiety remained low. Several life conditions predicted current emotional state.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The thesis reports on the strategic environmental assessment of Yalumba's 'Commitment to sustainable winemaking' programme. The case study identified the benefits, as well as shortcomings, of the wine firm's commitment to sustainability in the context of plausible future scenarios under the influence of various drivers of change, prominent amongst which was climate change.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Despite being the most widely distributed and cultured freshwater crayfish species in Australia, relatively little is known about the ecology of Cherax destructor outside of captivity. Similarly, few ecological studies have been conducted on the large and threatened stream dwelling Australian freshwater crayfish Euastacus bispinosus. A series of seasonal sampling surveys over two years investigated the population structure, life history and reproductive timing of C. destructor in fire dam habitats, and of E. bispinosus in channel (stream) habitats, in the Grampians National Park in south-west Victoria, Australia. Cherax destructor individuals in the largest size class (50 – 59.95 mm OCL) were not abundant during the study, while those belonging to the 0 – 9.95 mm OCL size class were more frequent in summer than at other times of year, suggesting synchronous recruitment in fire dam habitats. Individuals in the reproductively active mid-size classes were also frequent in summer. For E. bispinosus, sex ratios in spring always favoured females, although there were no clear trends for other times of year. Gravid E. bispinosus females were found in winter and spring throughout the study, and were sexually mature at a smaller size than has previously been reported.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this article, the difficulties some Australian university students experience in academic learning environments are explored. Particular attention is given to the experiences of students whose difficulties are often portrayed as intrinsic to them, and who are diagnosed as having learning disabilities or 'disorders'. In so doing, dominant neuro-psychological perspectives on students' learning 'problems' are challenged, broadening the discussion to include sociocultural explanations of students' difficulties. Research that foregrounds these students' own accounts of their problems is reported, identifying a number of tests of time, association and dissimulation that they experience in coming to terms with the particular institutional requirements of university life. At the very least, these explanations draw attention to the need for university teaching scholars to also be learners, and to consider their own practices in the construction of learning difficulties for their students.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Objective: To investigate the role of medical emergency teams in end-of-life care planning.

Design: One month prospective audit of medical emergency team calls.

Setting: Seven university-affiliated hospitals in Australia, Canada, and Sweden.

Patients: Five hundred eighteen patients who received a medical emergency team call over 1 month.

Interventions: None.

Measurements and Main Results: There were 652 medical emergency team calls in 518 patients, with multiple calls in 99 (19.1%) patients. There were 161 (31.1%) patients with limitations of medical therapy during the study period. The limitation of medical therapy was instituted in 105 (20.3%) and 56 (10.8%) patients before and after the medical emergency team call, respectively. In 78 patients who died with a limitation of medical therapy in place, the last medical emergency team review was on the day of death in 29.5% of patients, and within 2 days in another 28.2%. Compared with patients who did not have a limitation of medical therapy, those with a limitation of medical therapy were older (80 vs. 66 yrs; p < .001), less likely to be male (44.1% vs. 55.7%; p .014), more likely to be medical admissions (70.8% vs. 51.3%; p < .001), and less likely to be admitted from home (74.5% vs. 92.2%, p < .001). In addition, those with a limitation of medical therapy were less likely to be discharged home (22.4% vs. 63.6%; p < .001) and more likely to die in hospital (48.4% vs. 12.3%; p < .001). There was a trend for increased likelihood of calls associated with limitations of medical therapy to occur out of hours (51.0% vs. 43.8%, p .089).

Conclusions: Issues around end-of-life care and limitations of medical therapy arose in approximately one-third of calls, suggesting a mismatch between patient needs for end-of-life care and resources at participating hospitals. These calls frequently occur in elderly medical patients and out of hours. Many such patients do not return home, and half die in hospital. There is a need for improved advanced care planning in our hospitals, and to confirm our findings in other organizations.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background: The number of patients from Aged Care presenting to acute care is increasing, many of whom have a life limiting illness.

Aims: To identify differences in relation to Aged Care Residents presenting to Emergency departments who died during a hospital admission compared to those who were referred to the hospital based palliative care.

Methods: Review of a stratified random sample of 90 Aged Care residents transferred to acute care who died during admission in 2009; half the sample received palliative care. Comparisons were made with regard to age; gender; co-morbidities; symptoms, investigations and active treatment; prior admissions and costs.

Results: The median age of patients was 87.5 years, 61% were female and 38% had three or more admissions in the year prior to death. Patients with a length of stay of four or more days were 2.98 times (CI, 95%:1.11-8.03) and patients with agitation were 3.08 (CI 95%:1.10- 8.64) times more likely to be referred to palliative care. Patients who received palliative care had significantly fewer investigations or active treatment in the 24 hours prior to their death (p< 0.01) and palliated patients had significantly lower average costs per day of admission ($1022, SD=$441) compared to those who were not palliated ($ 831; SD= $ 1041) (p< 0.001).

Discussion: Our study indicates there is a difference between dying patients who received palliative care compared to those who did not in an acute care setting. Further research into the outcomes of patients discharged back to Aged Care facilities for palliative care warrants investigation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Fundamental ecological research is both intrinsically interesting and provides the basic knowledge required to answer applied questions of importance to the management of the natural world. The 100th anniversary of the British Ecological Society in 2013 is an opportune moment to reflect on the current status of ecology as a science and look forward to high-light priorities for future work. To do this, we identified 100 important questions of fundamental importance in pure ecology. We elicited questions from ecologists working across a wide range of systems and disciplines. The 754 questions submitted (listed in the online appendix) from 388 participants were narrowed down to the final 100 through a process of discussion, rewording and repeated rounds of voting. This was done during a two-day workshop and thereafter. The questions reflect many of the important current conceptual and technical pre-occupations of ecology. For example, many questions concerned the dynamics of environmental change and complex ecosystem interactions, as well as the interaction between ecology and evolution. The questions reveal a dynamic science with novel subfields emerging. For example, a group of questions was dedicated to disease and micro-organisms and another on human impacts and global change reflecting the emergence of new subdisciplines that would not have been foreseen a few decades ago. The list also contained a number of questions that have perplexed ecologists for decades and are still seen as crucial to answer, such as the link between population dynamics and life-history evolution. Synthesis. These 100 questions identified reflect the state of ecology today. Using them as an agenda for further research would lead to a substantial enhancement in understanding of the discipline, with practical relevance for the conservation of biodiversity and ecosystem function.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The pace-of-life syndrome (POLS) hypothesis specifies that closely related species or populations experiencing different ecological conditions should differ in a suite of metabolic, hormonal and immunity traits that have coevolved with the life-history particularities related to these conditions. Surprisingly, two important dimensions of the POLS concept have been neglected: (i) despite increasing evidence for numerous connections between behavioural, physiological and life-history traits, behaviours have rarely been considered in the POLS yet; (ii) the POLS could easily be applied to the study of covariation among traits between individuals within a population. In this paper, we propose that consistent behavioural differences among individuals, or personality, covary with life history and physiological differences at the within-population, interpopulation and interspecific levels. We discuss how the POLS provides a heuristic framework in which personality studies can be integrated to address how variation in personality traits is maintained within populations.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

As argued by Norman Bryson, the still-life genre is sorely neglected by theorists and critics, largely because its concern with ‘low-plane reality’ (everyday items and acts) has obscured its genuine relevance to material thinking. By reappraising rather than abandoning the genre’s traditional themes of death and time—using a cross-cultural, Chinese-Western approach—it is possible to re-energise materialisms of time, writing and death within still life. Such a move depends above all on a re-evaluation of still life as ‘Vanitas’—the term which to date has unified, and more to the point limited, traditional still-life understandings of death and time. This article tracks a more explosive and creative materialism of still life simultaneously through the specifically Chinese approach to death (which includes the ‘Yin Yang’ 阴阳 as a sort of author of time) and via Gilles Deleuze’s cinematic philosophy of the time-image; what connects these is the very Deleuzean notion of time that subtends Chinese engagements with death. In this way, the still-life genre may be recovered from its current critical and theoretical malaise. Reconnecting with practice is a crucial aspect of this recovery, and so in its early stages this article analyses an example of still-life, creative non-fiction (authored by Cher Coad), and it concludes by establishing the value of this potentially ‘new chapter of the “still life” genre’ (in Matilde Marcolli’s terms) for the cross-artform analysis of the short story ‘Nhill’ (authored by Patrick West). Analysis, though, is only half the picture: a fully recovered still-life genre would see theory and practice endlessly circulating through each other, spurring on practice and impelling theory. Coad’s and West’s literary examples are introduced in the hope that they might trigger fresh theoretical and practice-based, still-life discoveries in prose and also in poetry.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background
Television (TV) viewing, a prevalent leisure-time sedentary behaviour independently related to negative health outcomes, appears to be higher in less educated and older adults. In order to tackle the social inequalities, evidence is needed about the underlying mechanisms of the association between education and TV viewing. The present purpose was to examine the potential mediating role of personal, social and physical environmental factors in the relationship between education and TV viewing among Australian 55–65 year-old adults.

Methods

In 2010, self-reported data was collected among 4082 adults (47.6% men) across urban and rural areas of Victoria, for the Wellbeing, Eating and Exercise for a Long Life (WELL) study. The mediating role of personal (body mass index [BMI], quality of life), social (social support from family and friends, social participation at proximal level, and interpersonal trust, social cohesion, personal safety at distal level) and physical environmental (neighbourhood aesthetics, neighbourhood physical activity environment, number of televisions) factors in the association between education and TV viewing time was examined using the product-of-coefficients test of MacKinnon based on multilevel linear regression analyses (conducted in 2012).

Results
Multiple mediating analyses showed that BMI (p ≤ 0.01), personal safety (p < 0.001), neighbourhood aesthetics (p ≤ 0.01) and number of televisions (p ≤ 0.01) partly explained the educational inequalities in older adult’s TV viewing. No proximal social factors mediated the education-TV viewing association.

Conclusions

Interventions aimed to reduce TV viewing should focus on personal (BMI) and environmental (personal safety, neighbourhood aesthetics, number of televisions) factors, in order to overcome educational inequalities in sedentary behaviour among older adults.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background
Cost-effectiveness analyses of interventions for older adults have traditionally focused on health status. There is increasing recognition of the need to develop new instruments to capture quality of life in a broader sense in the face of age-associated increasing frailty and declining health status, particularly in the economic evaluation of aged and social care interventions which may have positive benefits beyond health. 


Objective
To explore the relative importance of health and broader quality of life domains for defining quality of life from the perspective of older South Australians.

Methods
Older adults (n=21) from a day rehabilitation facility in Southern Adelaide, South Australia attended one of two audiorecorded focus groups. A mixed methods (qualitative and quantitative) approach was adopted. The study included three main components. Firstly, a general group discussion on quality of life and the factors of importance in defining quality of life. Secondly, a structured ranking exercise in which individuals were asked to rank domains from the brief Older People’s Quality of Life questionnaire (OPQOL-brief) and Adult Social Care Outcomes Toolkit (ASCOT) in order of importance. Thirdly, participants were asked to self-complete the Euroqol (EQ-5D) a measure of health status, and two broader quality of life measures: the OPQOL-brief and ASCOT.

Results
Mean scores on the EQ-5D, OPQOL-brief and ASCOT were 0.71 (SD 0.20, range 0.06-1.00), 54.6 (SD 5.5, range 38-61) and 0.87 (SD 0.13, range 0.59-1.00) respectively, with higher scores reflecting better ratings of QOL. EQ-5D scores were positively associated with OPQOL-brief (rho: .730, p<.01), but not ASCOT. Approximately half (52.4%) of the respondents ranked either “health” or “psychological and emotional well- being” as the domain most important to their quality of life. However, one-third (33.3%) of the total sample ranked a non-health domain from the ASCOT or OPQOL-brief (safety, dignity, independence) as the most important contributing factor to their overall quality of life. Qualitative analysis of focus group transcripts supported the high value of both health-related (health, psychological well-being) and social (independence, safety) domains to quality of life.

Conclusions
Older adults value both health and social domains as important to their overall quality of life. Future economic evaluations of health, community and aged-care services for older adults should include assessment of both healthrelated and broader aspects quality of life.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

MasterFoods wetlands exhibit phytoplankton communities, yet no zooplankton to consume them. Macrophytes were planted to improve the water quality. However a lack of oxygen, methane production and highly soluble salts in the wetland water potentially disrupted osmoregulation mechanisms in both colonising zooplankton and submerged macrophytes, thereby inhibiting their survival.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background The relationship between unemployment and suicide may be sensitive to demographic factors, national unemployment rates, and length of time without employment. This study investigated these factors in relation to suicide in Australia for the period 1985–2006, in an ecological study. Methods The outcome variable was annual suicide rate by age group, sex and the eight states and territories over 22 years of observation (total observations=1760). The main predictor variable was the average duration of unemployment in the population, categorised into three time periods (<2 weeks, 2–4 weeks, >4 weeks). Poisson regression models were used to investigate the relationship between duration of unemployment and suicide over the years 1985–2006 in a series of cross-sectional analyses. Interaction analyses indicated significant differences during periods of declining or increasing labour market opportunity and by age group. Results During periods of declining unemployment rates in the country, longer durations of unemployment were associated with higher male suicide rates. During periods of increasing unemployment in the country, longer unemployment duration was associated with lower male suicide rates. Effect modification was also apparent by age-group, with stronger associations between unemployment duration and male suicide evident in those aged 25–34 and 55–64, and weaker associations in those aged 15–24 and 44–54 years. Longer length of unemployment was not associated with an increase in female suicide rates. Conclusions The labour market opportunities in Australia modified the effect of duration of unemployment on suicide, and the effect was more prominent in men and older age groups. This may reflect social norms and acceptability about unemployment, as well as life-stage influences associated with transitions into and out of the labour market.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Climate change modelers predict increasingly frequent “extreme events,” so it is critical to quantify whether organismal responses (such as reproductive output) measured over the range of usual climatic conditions can predict responses under more extreme conditions. In a 20-year field study on water pythons (Liasis fuscus), we quantified the effects of climatically driven annual variation in food supply on demographic traits of female pythons (feeding rate, body size, body mass, and reproductive output). Reaction norms linking food supply to feeding rates and residual body mass were broadly linear, whereas norms linking food supply to female body size became curvilinear when a dramatic (flooding-induced) famine reduced the mean body size at sexual maturity. Thus, the reaction norms recorded over 16 years of “normal” (albeit highly variable) climatic conditions gave little insight into the population's response to a more extreme nutritional crisis.