38 resultados para Human ecology - History

em University of Queensland eSpace - Australia


Relevância:

90.00% 90.00%

Publicador:

Resumo:

Evidence demonstrates that the digital divide is deepening despite strategies mobilized worldwide to reduce it. In disadvantaged communities, beyond training and infrastructural issues, there often lies a range of cultural and historically formed relationships that affect people's adoption of ICTs. This article presents an analysis of local resident's engagement with their council's pilot project to develop a computer facility in their community center. We ask, to what extent can people in poor urban communities, once trained, be expected to volunteer to work on furthering community education and development in ICTs in their local area? Findings indicate four patterns of individual engagement with the computer project: reflexive, utilitarian, distributive, and nonparticipatory. It is argued that local people engaged with the intervention in historically patterned and locally distinctive ways that served immediate personal and pragmatic ends. They did not adopt the long-term strategic goals of the council or university.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Aim: The aim of this study was to characterize the bacterial community adhering to the mucosa of the terminal ileum, and proximal and distal colon of the human digestive tract. Methods and Results: Pinch samples of the terminal ileum, proximal and distal colon were taken from a healthy 35-year-old, and a 68-year-old subject with mild diverticulosis. The 16S rDNA genes were amplified using a low number of PCR cycles, cloned, and sequenced. In total, 361 sequences were obtained comprising 70 operational taxonomic units (OTU), with a calculated coverage of 82.6%. Twenty-three per cent of OTU were common to the terminal ileum, proximal colon and distal colon, but 14% OTU were only found in the terminal ileum, and 43% were only associated with the proximal or distal colon. The most frequently represented clones were from the Clostridium group XIVa (24.7%), and the Bacteroidetes (Cytophaga-Flavobacteria-Bacteroides ) cluster (27.7%). Conclusion: Comparison of 16S rDNA clone libraries of the hindgut across mammalian species confirms that the distribution of phylogenetic groups is similar irrespective of the host species. Lesser site-related differences within groups or clusters of organisms, are probable. Significance and Impact: This study provides further evidence of the distribution of the bacteria on the mucosal surfaces of the human hindgut. Data contribute to the benchmarking of the microbial composition of the human digestive tract.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

To compare the incidence of foetal malformations (FMs) in pregnant women with epilepsy treated with different anti-epileptic drugs (AED) and doses, and the influence of seizures, family and personal history, and environmental factors. A prospective, observational, community-based cohort study. Methods. A voluntary, Australia-wide, telephone-interview-based register prospectively enrolling three groups of pregnant women: taking AEDs for epilepsy; with epilepsy not taking AEDs; taking AEDs for a non-epileptic indication. Four hundred and fifty eligible women were enrolled over 40 months. Three hundred and ninety six pregnancies had been completed, with 7 sets of twins, for a total of 403 pregnancy outcomes. Results. 354 (87.8%) pregnancy outcomes resulted in a healthy live birth, 26 (6.5%) had a FM, 4 (1%) a death in utero, 1 (0.2%) a premature labour with stillbirth, 14 (3.5%) a spontaneous abortion and 4 lost to follow-up. The FM rate was greater in pregnancies exposed to sodium valproate (VPA) in the first trimester (116.0%) compared with those exposed to all other AEDs (16.0% vs. 2.4%, P < 0.01) or no AEDs (16.0% vs. 3.1 %, P < 0.01). The mean daily dose of VPA taken in pregnancy with FMs was significantly greater than in those without (11975 vs: 1128 mg, P < 0.01). The incidence of FM with VPA doses greater than or equal to 1100 mg was 30.2% vs. 3.2% with doses < 1100 mg (P < 0.01). Conclusions. There is a dose-effect relationship for FM and exposure to VPA during the first trimester of pregnancy, with higher doses of VPA associated with a significantly greater risk than with lower doses or with other AEDs. These results highlight the need to limit, where possible, the dose of VPA in pregnancy. (C) 2004 Elsevier Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

After generally discussing models in ecology and economics that combine competition, optimization, and evolution, this article concentrates on models of intraspecific competition. It demonstrates the importance of diversity/inequalities within populations of species and other environments for the sustainability of their populations, given the occurrence of environmental change. This is demonstrated both for scramble (open-access) and contest competition. Implications are drawn for human populations and industrial organization. The possibility is raised that within-industry competition may not always exist between firms in all stages of the development of a new industry. Policy implications are considered. For example, it is argued that policies designed to encourage intense business competition and maximum economic efficiency have the drawback of eventually making industries highly vulnerable to exogenous economic changes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

'Free will' and its corollary, the concept of individual responsibility are keystones of the justice system. This paper shows that if we accept a physics that disallows time reversal, the concept of 'free will' is undermined by an integrated understanding of the influence of genetics and environment on human behavioural responses. Analysis is undertaken by modelling life as a novel statistico-deterministic version of a Turing machine, i.e. as a series of transitions between states at successive instants of time. Using this model it is proven by induction that the entire course of life is independent of the action of free will. Although determined by prior state, the probability of transitions between states in response to a standard environmental stimulus is not equal to 1 and the transitions may differ quantitatively at the molecular level and qualitatively at the level of the whole organism. Transitions between states correspond to behaviours. It is shown that the behaviour of identical twins (or clones), although determined, would be incompletely predictable and non-identical, creating an illusion of the operation of 'free will'. 'Free will' is a convenient construct for current judicial systems and social control because it allows rationalization of punishment for those whose behaviour falls outside socially defined norms. Indeed, it is conceivable that maintenance of ideas of free will has co-evolved with community morality to reinforce its operation. If the concept is free will is to be maintained it would require revision of our current physical theories.

Relevância:

30.00% 30.00%

Publicador:

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Humans are primates. We have evolved from common ancestors and the evolution of the human body is becoming increasingly clear as the archeological record expands. But for most people the gap between humans and animals lies in the mind, not in the body. And minds do not fossilise. To reconstruct the evolution of mind, scholars have thus increasingly looked to our closest relatives for clues. Here I discuss four ways in which the study of primates may inform such reconstruction: fact-finding, phylogenetic reconstruction, analogy, and regression models. Knowledge about primates can help us bridge the gap. Extinction of our closest relatives, on the other hand, would not only deplete that source of information but also increase the apparent differences between animal and human minds. It is likely that we have a long history of displacing closely related species, including the other hominids, leading us to appear ever more unique.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The green sea turtle is one of the long-lived species that comprise the charismatic marine megafauna. The green turtle has a long history of human exploitation with some stocks extinct. Here we report on a 30-year study of the nesting abundance of the green turtle stock endemic to the Hawaiian Archipelago. We show that there has been a substantial long-term increase in abundance of this once seriously depleted stock following cessation of harvesting since the 1970s. This population increase has occurred in a far shorter period of time than previously thought possible. There was also a distinct 3-4 year periodicity in annual nesting abundance that might be a function of regional environmental stochasticity that synchronises breeding behaviour throughout the Archipelago. This is one of the few reliable long-term population abundance time series for a large long-lived marine species, which are needed for gaining insights into the recovery process of long-lived marine species and long-term ecological processes. (C) 2003 Elsevier Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Birds show striking interspecific variation in their use of carotenoid-based coloration. Theory predicts that the use of carotenoids for coloration is closely associated with the availability of carotenoids in the diet but, although this prediction has been supported in single-species studies and those using small numbers of closely related species, there have been no broad-scale quantitative tests of the link between carotenoid coloration and diet. Here we test for such a link using modern comparative methods, a database on 140 families of birds and two alternative avian phylogenies. We show that carotenoid pigmentation is more common in the bare parts (legs, bill and skin) than in plumage, and that yellow coloration is more common than red. We also show that there is no simple, general association between the availability of carotenoids in the diet and the overall use of carotenoid-based coloration. However, when we look at plumage coloration separately from bare part coloration, we find there is a robust and significant association between diet and plumage coloration, but not between diet and bare part coloration. Similarly, when we look at yellow and red plumage colours separately, we find that the association between diet and coloration is typically stronger for red coloration than it is for yellow coloration. Finally, when we build multivariate models to explain variation in each type of carotenoid-based coloration we find that a variety of life history and ecological factors are associated with different aspects of coloration, with dietary carotenoids only being a consistent significant factor in the case of variation in plumage. All of these results remain qualitatively unchanged irrespective of the phylogeny used in the analyses, although in some cases the precise life history and ecological variables included in the multivariate models do vary. Taken together, these results indicate that the predicted link between carotenoid coloration and diet is idiosyncratic rather than general, being strongest with respect to plumage colours and weakest for bare part coloration. We therefore suggest that, although the carotenoid-based bird plumage may a good model for diet-mediated signalling, the use of carotenoids in bare part pigmentation may have a very different functional basis and may be more strongly influenced by genetic and physiological mechanisms, which currently remain relatively understudied.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Many long-lived marine species exhibit life history traits. that make them more vulnerable to overexploitation. Accurate population trend analysis is essential for development and assessment of management plans for these species. However, because many of these species disperse over large geographic areas, have life stages inaccessible to human surveyors, and/or undergo complex developmental migrations, data on trends in abundance are often available for only one stage of the population, usually breeding adults. The green turtle (Chelonia mydas) is one of these long-lived species for which population trends are based almost exclusively on either numbers of females that emerge to nest or numbers of nests deposited each year on geographically restricted beaches. In this study, we generated estimates of annual abundance for juvenile green turtles at two foraging grounds in the Bahamas based on long-term capture-mark-recapture (CMR) studies at Union Creek (24 years) and Conception Creek (13 years), using a two-stage approach. First, we estimated recapture probabilities from CMR data using the Cormack-Jolly-Seber models in the software program MARK; second, we estimated annual abundance of green turtles. at both study sites using the recapture probabilities in a Horvitz-Thompson type estimation procedure. Green turtle abundance did not change significantly in Conception Creek, but, in Union Creek, green turtle abundance had successive phases of significant increase, significant decrease, and stability. These changes in abundance resulted from changes in immigration, not survival or emigration. The trends in abundance on the foraging grounds did not conform to the significantly increasing trend for the major nesting population at Tortuguero, Costa Rica. This disparity highlights the challenges of assessing population-wide trends of green turtles and other long-lived species. The best approach for monitoring population trends may be a combination of (1) extensive surveys to provide data for large-scale trends in relative population abundance, and (2) intensive surveys, using CMR techniques, to estimate absolute abundance and evaluate the demographic processes' driving the trends.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The history of human experimentation in the twelve years between Hitler's rise to power and the end of the Second World War is notorious in the annals of the twen- tieth century. The horrific experiments conducted at Dachau, Auschwitz, Ravens- brueck, Birkenau, and other National Socialist concentration camps reflected an extreme indifference to human life and human suffering. Unfortunately, they do not reflect the extent and complexity of the human experiments undertaken in the years between 1933 and 1945. Following the prosecution of twenty-three high-ranking National Socialist physicians and medical administrators for war crimes and crimes against humanity in the Nuremberg Medical Trial (United States v. Karl Brandt et al.), scholars have rightly focused attention on the nightmarish researches con- ducted by a small group of investigators on concentration camp inmates. Less well known are alternative pathways that brought investigators to undertake human ex- perimentation in other laboratories, settings, and nations.