8 resultados para Size-Ramsey numbers

em Deakin Research Online - Australia


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The Parsis of India are perhaps the world’s smallest ethnic community whose entrepreneurial contribution to India has far exceeded their size in numbers. This paper traces the rise of the Parsis as entrepreneurs in Indian society from the 16th century in Surat and later Mumbai to their significant presence today amongst India’s major business houses with household names such as the Tatas, Wadias and Godrej.

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The decline of the Black-eared Miner Manorina melanotis has been caused primarily by habitat degradation and vegetation clearance. To better direct conservation actions for this species there was a need to assess habitat requirements on a regional-scale and to estimate the population size using quantitative methods. We used vegetation mapping and the current distribution of the Black-eared Miner to determine regional-scale habitat requirements. These findings were combined with the results of distance sampling to provide population estimates. The species is restricted to large tracts of intact mallee in the Murray Mallee of southeastern Australia that have not been burnt for at least 45 years. The density· of Black-eared Miners is highest in areas that are dominated by mallee- Triodia associations and have not been intensively grazed. The Bookmark Biosphere Reserve supports an estimated 501 (270-927, 95% CI) colonies, containing 3758 (2026-6954) phenotypically pure Black-eared Miners, 2255 (1 215-4170) hybrids and small numbers of Yellow-throated Miners Manorina flavigula. However, the effective population size is considerably smaller (390 Black-eared Miners '(21 0-726) and 234 hybrids (126-433)), due to a skewed adult sex ratio (1 female: 1.81 males) and complex social organization. A smaller population also persists in the Murray Sunset National Park containing 53 (32-85) Black-eared Miner/hybrid colonies. Both populations face a high risk of extinction from large-scale wildfire. The endangered status of the species under IUCN criteria remains warranted.

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1. Long-distance dispersal (LDD) is important in plants of dynamic and ephemeral habitats. For plants of dynamic wetland habitats, waterfowl are generally considered to be important LDD vectors. However, in comparison to the internal (endozoochorous) dispersal of terrestrial plants by birds, endozoochorous dispersal of wetland plants by waterfowl has received little attention. We quantified the capacity for endozoochorous dispersal of wetland plants by waterfowl and identified the mechanisms underlying successful dispersal, by comparing the dispersal capacities of a large number of wetland plant species.

2. We selected 23 common plant species from dynamic wetland habitats and measured their seed characteristics. We fed seeds of all species to mallards (Anas platyrhynchos), a common and highly omnivorous duck species, and quantified seed gut survival, gut passage speed and subsequent germination. We then used a simple model to calculate seed dispersal distances.

3. In total 21 of the 23 species can be dispersed by mallards, with intact seed retrieval and subsequent successful germination of up to 32% of the ingested seeds. The species that pass fastest through the digestive tract of the mallards are retrieved in the greatest numbers (up to 54%) and germinate best (up to 87%). These are the species with the smallest seeds. Seed coat thickness plays only a minor role in determining intact passage through the mallard gut, but determines if ingestion enhances or reduces germination in comparison to control seeds.

4. Model calculations estimate that whereas the largest seeds can hardly be dispersed by mallards, most seeds can be dispersed up to 780 km, and the smallest seeds up to 3000 km, by mallards during migration.

5. Synthesis. This study demonstrates the mechanism underlying successful endozoochorous dispersal of wetland plant seeds by mallards: small seed size promotes rapid, and hence intact and viable, passage through the mallard gut. Mallards can disperse wetland plant seeds of all but the largest-seeded species successfully in relatively large numbers (up to 32% of ingested seeds) over long distances (up to thousands of kilometres) and are therefore important dispersal vectors.

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This paper reports on the effectiveness of an intervention designed to improve nursing students’ conceptual understanding of decimal numbers. Results of recent intervention studies have indicated some success at improving nursing students’ numeracy through practice in applying procedural rules for calculation and working in real or simulated practical contexts. However, in this we identified a fundamental problem: a significant minority of students had an inadequate understanding of decimal numbers. The intervention aimed to improve nursing students’ basic understanding of the size of decimal numbers, so that, firstly, calculation rules are more meaningful, and secondly, students can interpret decimal numbers (whether digital output or results of calculations) sensibly. A well-researched, time-efficient diagnostic instrument was used to identify individuals with an inadequate understanding of decimal numbers. We describe a remedial intervention that resulted in significant improvement on a delayed post-intervention test. We conclude that nurse educators should consider diagnosing and, as necessary, plan for remediation of students’ foundational understanding of decimal numbers before teaching procedural rules.

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Aim: Tracking the dispersal patterns and habitat use of migratory species is necessary to delineate optimal areas for protection, with large sample sizes being more representative of the population. Here, we examine the dispersal patterns of a key Mediterranean loggerhead turtle (Caretta caretta) breeding population to identify priority foraging sites for protection. Location: Zakynthos Island, Greece and the wider Mediterranean. Method: We examined the dispersal patterns and foraging sites of 75 adult loggerheads (n = 38 males and 37 females) tracked from the breeding area of Zakynthos Island (Greece) from 2004 to 2011. We then combined our data with published sea turtle literature to identify key foraging sites for protection. Results: While both males and females exhibited similar dispersal patterns, about 25% males remained < 100 km of Zakynthos, whereas all females (except one) migrated > 200 km. Integration of our data with the wider literature isolated 10 core sites in proximity to existing protected areas, which could potentially protect 64% of the Zakynthos population, while five sites support individuals from at least 10 other loggerhead breeding populations. Main conclusions: Due to the widespread availability of neritic foraging grounds across the Mediterranean, sea turtles from Zakynthos exhibit disparate dispersal patterns. However, protecting only a few objectively defined important sites can encompass a large proportion of the foraging areas used and hence have considerable conservation benefit.

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Gambling prevalence studies are typically conducted within a single (landline) telephone sampling frame. This practice continues, despite emerging evidence that significant differences exist between landline and mobile (cell) phone only households. This study utilised a dual-frame (landline and mobile) telephone sampling methodology to cast light on the extent of differences across groups of respondents in respect to demographic, health, and gambling characteristics.

A total of 2,014 participants from across Australian states and 
territories ranging in age from 18 to 96 years participated. Interviews were conducted using computer assisted telephone interviewing technology where 1,012 respondents from the landline sampling frame and 1,002 from the mobile phone sampling frame completed a questionnaire about gambling and other health behaviours. Responses across the landline sampling frame, the mobile phone sampling frame, and the subset of the mobile phone sampling frame that possessed a mobile phone only (MPO) were contrasted.

The findings 
revealed that although respondents in the landline sample (62.7 %) did not significantly differ from respondents in the mobile phone sample (59.2 %) in gambling participation in the previous 12 months, they were significantly more likely to have gambled in the previous 12 months than the MPO sample (56.4 %). There were no significant differences in internet gambling participation over the previous 12 months in the landline sample (4.7 %), mobile phone sample (4.7 %) and the MPO sample (5.0 %). However, endorsement of lifetime problem gambling on the NODS-CLiP was significantly higher within the mobile sample (10.7 %) and the MPO sample (14.8 %) than the landline sample (6.6 %).

Our research 
supports previous findings that reliance on a traditional landline telephone sampling approach effectively excludes distinct subgroups of the population from being represented inresearch findings. Consequently, we suggest that research best practice necessitates the use of a dual- rame sampling methodology. Despite inherent logistical and cost issues, this approach  needs to become the norm in gambling survey research.

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Road-killed animals are easy and inexpensive to survey, and may provide information about species distributions, abundances, and mortality rates. As with any sampling method, however, we need to explore methodological biases in such data. First, how does an animal's behavior (e.g., use of the center vs. periphery of the road) influence its vulnerability to vehicular traffic? Second, how rapidly do post-mortem processes (scavenging by other animals, destruction or displacement by subsequent vehicles) change the numbers and locations of roadkills? Our surveys of anurans on a highway in tropical Australia show that different anuran species are distributed in different ways across the width of the road, and that locations of live versus dead animals sometimes differ within a species. Experimental trials show that location on the road affects the probability of being hit by a vehicle, with anurans in the middle of the road begin hit 35% more often than anurans on the edges; thus, center-using species are more likely to be hit than edge-using taxa. The magnitude of post-mortem displacement and destruction by subsequent vehicles depended on anuran species and body size. The mean parallel displacement distance was 122.7 cm, and carcasses of thin-skinned species exhibited greater post-mortem destruction. Scavenging raptors removed 73% of carcasses, most within a few hours of sunrise. Removal rates were biased with respect to size and species. Overall, our studies suggest that investigators should carefully evaluate potential biases before using roadkill counts to estimate underlying animal abundances or mortality rates.

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Size-selective harvest of fish and crustacean populations has reduced stock numbers, and led to reduced growth rates and earlier maturation. In contrast to the focus on size-selective effects of harvest, here, we test the hypothesis that fishing may select on life-history traits (here, growth rate) via behaviour, even in the absence of size selection. If true, then traditional size-limits used to protect segments of a population cannot fully protect fast growers, because at any given size, fast-growers will be more vulnerable owing to bolder behaviour. We repeatedly measured individual behaviour and growth of 86 crayfish and found that fast-growing individuals were consistently bold and voracious over time, and were subsequently more likely to be harvested in single- and group-trapping trials. In addition, there was some indication that sex had independent effects on behaviour and trappability, whereby females tended to be less active, shyer, slower-growing and less likely to be harvested, but not all these effects were significant. This study represents, to our knowledge, the first across-individual support for this hypothesis, and suggests that behaviour is an important mechanism for fishing selectivity that could potentially lead to evolution of reduced intrinsic growth rates.