136 resultados para Kullback-Leibler Divergence


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The intermediate leaf-nosed bat (Hipposideros larvatus) is a medium-sized bat distributed throughout the Indo-Malay region. In north-east India, bats identified as H. larvatus captured at a single cave emitted echolocation calls with a bimodal distribution of peak frequencies, around either 85 kHz or 98 kHz. Individuals echolocating at 85 kHz had larger ears and longer forearms than those echolocating at 98 kHz, although no differences were detected in either wing morphology or diet, suggesting limited resource partitioning. A comparison of mitochondrial control region haplotypes of the two phonic types with individuals sampled from across the Indo-Malay range supports the hypothesis that, in India, two cryptic species are present. The Indian 98-kHz phonic bats formed a monophyletic clade with bats from all other regional populations sampled, to the exclusion of the Indian 85-kHz bats. In India, the two forms showed 12–13% sequence divergence and we propose that the name Hipposideros khasiana for bats of the 85-kHz phonic type. Bats of the 98-kHz phonic type formed a monophyletic group with bats from Myanmar, and corresponded to Hipposideros grandis, which is suggested to be a species distinct from Hipposideros larvatus. Differences in echolocation call frequency among populations did not reflect phylogenetic relationships, indicating that call frequency is a poor indicator of evolutionary history. Instead, divergence in call frequency probably occurs in allopatry, possibly augmented by character displacement on secondary contact to facilitate intraspecific communication.

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Fossils provide the principal basis for temporal calibrations, which are critical to the accuracy of divergence dating analyses. Translating fossil data into minimum and maximum bounds for calibrations is the most important, and often least appreciated, step of divergence dating. Properly justified calibrations require the synthesis of phylogenetic, paleontological, and geological evidence and can be difficult for non-specialists to formulate. The dynamic nature of the fossil record (e.g., new discoveries, taxonomic revisions, updates of global or local stratigraphy) requires that calibration data be updated continually lest they become obsolete. Here, we announce the Fossil Calibration Database (http://fossilcalibrations.org), a new open-access resource providing vetted fossil calibrations to the scientific community. Calibrations accessioned into this database are based on individual fossil specimens and follow best practices for phylogenetic justification and geochronological constraint. The associated Fossil Calibration Series, a calibration-themed publication series at Palaeontologia Electronica, will serve as one key pipeline for peer-reviewed calibrations to enter the database.

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I argue that a divergence between popular culture as “object” and “subject” of journalism emerged during the nineteenth century in Britain. It accounts not only for different practices of journalism, but also for differences in the study of journalism, as manifested in journalism studies and cultural studies respectively. The chapter offers an historical account to show that popular culture was the source of the first mass circulation journalism, via the pauper press, but that it was later incorporated into the mechanisms of modern government for a very different purpose, the theorist of which was Walter Bagehot. Journalism’s polarity was reversed – it turned from “subjective” to “objective.” The paper concludes with a discussion of YouTube and the resurgence of self-made representation, using the resources of popular culture, in current election campaigns. Are we witnessing a further reversal of polarity, where popular culture and self-representation once again becomes the “subject” of journalism?

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The implementation of ‘good governance’ in Indonesia’s regional government sector became a central tenet in governance research following the introduction of the national code for governance in 2006. The code was originally drafted in 1999 as a response to the Asian financial crises and many cases of unearthed corruption, collusion, and nepotism. It was reviewed in 2001 and again in 2006 to incorporate relevant political, economical, and social developments. Even though the national code exists along with many regional government decrees on good governance, the extent of implementation of the tenets of good governance in Indonesia’s regional government is still questioned. Previous research on good governance implementation in Indonesian regional government (Mardiasmo, Barnes and Sakurai, 2008) identified differences in the nature and depth of implementation between various Indonesian regional governments. This paper analyses and extends this recent work and explores key factors that may impede the implementation and sustained application of governance practices across regional settings. The bureaucratic culture of Indonesian regional government is one that has been shaped for over approximately 30 years, in particular during that of the Soeharto regime. Previous research on this regime suggests a bureaucratic culture with a mix of positive and negative aspects. On one hand Soeharto’s regime resulted in strong development growth and strong economic fundamentals, resulting in Indonesia being recognised as one of the Asian economic tigers prior to the 1997 Asian financial crises. The financial crises however revealed a bureaucratic culture that was rife with corruption, collusion, and nepotism. Although subsequent Indonesian governments have been committed to eradicating entrenched practices it seems apparent that the culture is ingrained within the bureaucracy and eradication of it will take time. Informants from regional government agree with this observation, as they identify good governance as an innovative mechanism and to implement it will mean a deviation from the “old ways.” Thus there is a need for a “changed” mind set in order to implement sustained governance practices. Such an exercise has proven to be challenging so far, as there is “hidden” resistance from within the bureaucracy to change its ways. The inertia of such bureaucratic cultures forms a tension against the opportunity for the implementation of good governance. From this context an emergent finding is the existence of a ‘bureaucratic generation gap’ as an impeding variable to enhanced and more efficient implementation of governance systems. It was found that after the Asian financial crises the Indonesian government (both at national and regional level) drew upon a wider human resources pool to fill government positions – including entrants from academia, the private sector, international institutions, foreign nationals and new graduates. It suggested that this change in human capital within government is at the core of this ‘inter-generational divide.’ This divergence is exemplified, at one extreme, by [older] bureaucrats who have been in-position for long periods of time serving during the extended Soeharto regime. The “new” bureaucrats have only sat in their positions since the end of Asian financial crisis and did not serve during Soeharto’s regime. It is argued that the existence of this generation gap and associated aspects of organisational culture have significantly impeded modernising governance practices across regional Indonesia. This paper examines the experiences of government employees in five Indonesian regions: Solok, Padang, Gorontalo, Bali, and Jakarta. Each regional government is examined using a mixed methodology comprising of on-site observation, document analysis, and iterative semi-structured interviewing. Drawing from the experiences of five regional governments in implementing good governance this paper seeks to better understand the causal contexts of variable implementation governance practices and to suggest enhancements to the development of policies for sustainable inter-generational change in governance practice across regional government settings.

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The purpose of this study was to identify the pedagogical knowledge relevant to the successful completion of a pie chart item. This purpose was achieved through the identification of the essential fluencies that 12–13-year-olds required for the successful solution of a pie chart item. Fluency relates to ease of solution and is particularly important in mathematics because it impacts on performance. Although the majority of students were successful on this multiple choice item, there was considerable divergence in the strategies they employed. Approximately two-thirds of the students employed efficient multiplicative strategies, which recognised and capitalised on the pie chart as a proportional representation. In contrast, the remaining one-third of students used a less efficient additive strategy that failed to capitalise on the representation of the pie chart. The results of our investigation of students’ performance on the pie chart item during individual interviews revealed that five distinct fluencies were involved in the solution process: conceptual (understanding the question), linguistic (keywords), retrieval (strategy selection), perceptual (orientation of a segment of the pie chart) and graphical (recognising the pie chart as a proportional representation). In addition, some students exhibited mild disfluencies corresponding to the five fluencies identified above. Three major outcomes emerged from the study. First, a model of knowledge of content and students for pie charts was developed. This model can be used to inform instruction about the pie chart and guide strategic support for students. Second, perceptual and graphical fluency were identified as two aspects of the curriculum, which should receive a greater emphasis in the primary years, due to their importance in interpreting pie charts. Finally, a working definition of fluency in mathematics was derived from students’ responses to the pie chart item.

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This study explored the beliefs and attitudes of cyclists and drivers regarding cyclist visibility, use of visibility aids and crashes involving cyclists and motorists. Data are presented for 1460 participants (622 drivers and 838 cyclists) and demonstrate that there are high rates of cyclist–vehicle crashes, many of which were reported to be due to the driver not seeing the cyclist in time to avoid a collision. A divergence in attitudes was also apparent in terms of attribution of responsibility in cyclist–vehicle conflicts on the road. While the use of visibility aids was advocated by cyclists, this was not reflected in self-reported wearing patterns, and cyclists reported that the distance at which they would be first recognised by a driver was twice that estimated by the drivers. Collectively, these results suggest that interventions should target cyclists’ use of visibility aids, which is less than optimal in this population, as well as re-educating both groups regarding visibility issues.

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The Wet Tropics bioregion of north-eastern Australia has been subject to extensive fluctuations in climate throughout the late Pliocene and Pleistocene. Cycles of rainforest contraction and expansion of dry sclerophyll forest associated with such climatic fluctuations are postulated to have played a major role in driving geographical endemism in terrestrial rainforest taxa. Consequences for the distributions of aquatic organisms, however, are poorly understood.The Australian non-biting midge species Echinocladius martini Cranston (Diptera: Chironomidae), although restricted to cool, well-forested freshwater streams, has been considered to be able to disperse among populations located in isolated rainforest pockets during periods of sclerophyllous forest expansion, potentially limiting the effect of climatic fluctuations on patterns of endemism. In this study, mitochondrial COI and 16S data were analysed for E. martini collected from eight sites spanning theWet Tropics bioregion to assess the scale and extent of phylogeographic structure. Analyses of genetic structure showed several highly divergent cryptic lineages with restricted geographical distributions. Within one of the identified lineages, strong genetic structure implied that dispersal among proximate (<1 km apart) streams was extremely restricted. The results suggest that vicariant processes, most likely due to the systemic drying of the Australian continent during the Plio-Pleistocene, might have fragmented historical E. martini populations and, hence, promoted divergence in allopatry.