103 resultados para Minimal Set


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In this paper, we rigorously prove that the complete set of Riemann tensor invariants given by Sneddon [J. Math. Phys. 40, 5905 (1999)] is both minimal and complete. Furthermore, we provide a two-stage algorithm for the explicit construction of polynomial syzygies relating any dependent Riemann tensor invariant to members of the complete set.

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Eased on field observations and compilation of data, a new stratigraphic concept, herein named the Permian-Triassic boundary stratigraphic set (PTBST), is proposed. The PTBST consists of, in ascending order, beds of claystone, limestone (or marl) and claystone. This boundary stratigraphic
set has been recognized at many sections in the Yangtze region of South China, with laterally stable lithological characters, the same or comparable biotas, comparable radiometric ages, and identical or similar magnetostratigraphic and chemostratigraphic signals. Therefore, the PTBST marks an isochronous unit and can serve as an important and effective marker set for regional and global correlations.
The important index fossils for the lowermost Triassic, Hindeodus parvus or Claraia, may be diachronous in their first occurrences with respect to the base of the PTBST and, therefore, should not be used as an exclusive indicator for the beginning of the Triassic. Rather more attention should
be paid to events, succession of events and/or event surfaces, which would potentially provide a more precise tool for high-resolution stratigraphic division and correlation.

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Phytoplankton primary productivity of eleven irrigation reservoirs located in five river basins in Sri Lanka was determined on a single occasion together with light climate and nutrient concentrations. Although area-based gross primary productivity (1.43–11.65 g O2 m−2 d−1) falls within the range already established for tropical water bodies, net daily rate was negative in three water bodies. Light-saturated optimum rates were found in water bodies, with relatively high algal biomass, but photosynthetic efficiency or specific rates were higher in water bodies with low algal biomass, indicating nutrient limitation or physiological adaptation of phytoplankton. Concentrations of micronutrients and algal biomass in the reservoirs are largely altered by high flushing rate resulting from irrigation release. Underwater light climate and nutrient availability control the rate of photosynthesis and subsequent areabased primary production to a great extent. However, morpho-edephic index or euphotic algal biomass in the most productive stratum of the water column is not a good predictor of photosynthetic capacity or daily rate of primary production of these shallow tropical irrigation reservoirs.

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In this paper, the impact of the size of the training set on the benefit from ensemble, i.e. the gains obtained by employing ensemble learning paradigms, is empirically studied. Experiments on Bagged/ Boosted J4.8 decision trees with/without pruning show that enlarging the training set tends to improve the benefit from Boosting but does not significantly impact the benefit from Bagging. This phenomenon is then explained from the view of bias-variance reduction. Moreover, it is shown that even for Boosting, the benefit does not always increase consistently along with the increase of the training set size since single learners sometimes may learn relatively more from additional training data that are randomly provided than ensembles do. Furthermore, it is observed that the benefit from ensemble of unpruned decision trees is usually bigger than that from ensemble of pruned decision trees. This phenomenon is then explained from the view of error-ambiguity balance.

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This paper presents key findings of a situational analysis of institutional and structural levels of HIV/AIDS-related discrimination in Beijing, China, with a focus on the area of health care. Initially slow to respond to the presence of HIV, China has altered its approach and enacted strict legislative protection for people living with HIV/AIDS (PLWHA). In order to determine whether this has altered discrimination against PLWHA, this study examined existing legislation and policy, and interviewed key informants working in health care and PLWHA. The overall findings revealed that discrimination in its many forms continued to occur in practice despite China's generally strong legislative protection, and it is the actual practice that is hindering PLWHAs' access to health services. A number of legislative and policy gaps that allow discrimination to occur in practice were also identified and discussed. The paper concludes with a call to rectify specific gaps between legislation, policy and practice. An understanding of the underlying factors that drive discrimination will also be necessary for effective strategic interventions to be developed and implemented.

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A reduced dynamics stabiliser for multi-machine power systems is presented in this paper. The design of the stabiliser is based on the theory of linear functional observers and the solution of a simple parameter optimisation problem. The order of the stabiliser could be as low as the number of machines in the system. The design is applied to an open-loop unstable multi-machine power system.

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Selecting a set of features which is optimal for a given task is a problem which plays an important role in a wide variety of contexts including pattern recognition, images understanding and machine learning. The paper describes an application of rough sets method to feature selection and reduction in texture images recognition. The proposed methods include continuous data discretization based on Kohonen neural network and maximum covariance, and rough set algorithms for feature selection and reduction. The experiments on trees extraction from aerial images show that the methods presented in this paper are practical and effective.

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Purpose: – The purpose of this paper is to examine and evaluate the internationalisation of Australian auditing standards by analysing the submissions to the Auditing and Assurance Standards Board's (AUASB) strategic directions paper (SDP) and comparing the proposed and approved strategic directions frameworks of the AUASB.

Design/methodology/approach
: – A content analysis of the submissions to the SDP is conducted to identify the extent of support, and arguments for and against the proposed strategic directions. This study attempts to find a link, if any, between the proposed strategic directions, the views expressed by the stakeholders, and the final set of strategic directions issued by Australia's Financial Reporting Council.

Findings: – Overall, the final set of strategic directions released in April 2005 are consistent with the views expressed in the submissions, which support minimal divergence from International Standards on Auditing (ISAs) and using the ISAs as the base for developing Australian auditing standards. Major changes from the SDP include a requirement for the AUASB to undertake research and monitor auditing standards issued by national standard setters. However, the AUASB is no longer obliged to contribute to the international standard arena and need only have regard to any program initiated by the International Auditing and Assurance Standards Board.

Research limitations/implications: – The findings of this study provide an insight into the future of Australia's role in the international arena and increase awareness of stakeholders' views on the international harmonisation of auditing standards.

Originality/value: – While there have been several studies examining the international harmonisation of accounting standards, there is comparatively little research on the international harmonisation of auditing standards. This paper attempts to address this void, in part, and contribute to the literature on the convergence of auditing standards with ISAs.

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Aim: The study's purpose was to describe patients' experiences of minimal conscious sedation during diagnostic and interventional cardiology procedures.

Methods:
Over a 6-week period, 119 consecutive patients (10% of annual throughput) from a major metropolitan hospital in Melbourne, Australia, were interviewed using a modified version of the American Pain Society Patient Outcome Questionnaire. Patients identified pain severity using a 10-point visual analogue scale and rated their overall comfort on a 6-point Likert scale ranging from very comfortable to very uncomfortable.

Results: Patients were aged 67.6 years (standard deviation 11.1), 70.8% were male, and the mean body mass index was 27.7 (standard deviation 4.8). Patients underwent diagnostic coronary angiography (67.5%), percutaneous coronary interventions (13.3%), or combined procedures (19.2%). Most patients (65%) were comfortable in the context of low-dose conscious sedation. Slight discomfort was reported by 26% of patients; 9% reported feeling uncomfortable primarily as a result of a combination of musculoskeletal pain, angina, and vasovagal symptoms experienced during the procedure. There was significant correlation (rho = .25, P = .01) between procedure length and patients' report of overall comfort, suggesting longer procedures were less comfortable for patients.

Conclusions:
The minimal sedation protocol was effective for the majority of patients; however, 9% of patients experienced significant discomfort related to preexisting conditions, highlighting the need for individual patient assessment before, during, and after the procedure.

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The physical adaptation, remaking and maintenance, or building of the house plays a significant role in immigrants’ sense of belonging to a community, especially in contexts of first generation elderly immigrants with minimal English language skills. Psychoanalytic theories propose that objects are integral to a subject’s identity, but that the path of effect between the subject and object is not causal or direct, rather it goes via the unconscious. This paper seeks to examine the relationship between immigrants and their houses through these theories adapting them to an analysis of the houses. It draws its data from field research of three elderly immigrant households. The iconography of the house has always been perceived as central to the analysis of dreams, here the thesis is that the house is the most significant object of the immigrant because it mediates the many worlds inherent to the migrant’s imaginary landscapes. The analysis will seek to understand this role of the house.

Secondly, while many houses in which migrants live can barely be differentiated in clear physical ways from the typology of houses built in Australia, the perception that they are different is a strong myth. At the least it has resulted in very little, if any, study of this vernacular of new Australian houses. It would be easy to argue that to build a house in Australia is the most important mode of assimilation because a way of life is intrinsically set by this suburban paradigm. But for the reason of this perception of difference I will explore an idea about ethnic aesthetics as a mode of resisting assimilation. In writing on taste in his seminal book, Distinction, the sociologist, Pierre Bourdieu, has argued that taste is a way of classifying people into classes, race, culture, but it is also a way for dominant and ruling classes to resist challenges from other parties, and maintain a particular hierarchy of society. In this case those other parties are ethnic communities in Australia whose tastes are not always the same as that of the dominant Anglo-Celtic community.

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Background – The olive oil phenolic, oleocanthal is a natural non-steroidal anti-inflammatory compound that irritates the oropharynx in a dose-dependent manner. It has been proposed that the biological activity of oleocanthal is partially responsible for the beneficial health effects of the Mediterranean diet. Virgin olive oil containing oleocanthal is often added as an ingredient in a number of cooked dishes and therefore it is of great importance to understand how best to preserve the putative health promoting benefits of this compound, as olive oil phenolics are
subject to heat degradation.

Objective – To investigate if oleocanthal is thermally degraded or its biological activity reduced during cooking.

Design – One extra virgin olive oil containing 54mg/kg oleocanthal was heated at varying temperatures (100°C, 170°C and 240°C) for set time periods (0, 1, 5, 20, 60, 90 min). Oleocanthal concentrations were quantified using HPLC and its biological activity determined with a taste bioassay measuring the intensity of throat irritation.

Outcomes – Results demonstrated that oleocanthal was heat stable compared with other olive oil phenolics, with a maximum loss of 16% as determined by HPLC analysis. In contrast, there was a significant decrease of up to 38% (p<0.05) in the biological activity of oleocanthal as determined by the taste bioassay.

Conclusions Minimal degradation of oleocanthal concentration was observed upon heating however a significant decrease in the biological activity of this compound was noted with extended heating time. This has important implications for health in that, consumers may be unable to reap all of the putative health benefits associated with oleocanthal when adding virgin olive oil as an ingredient to dishes requiring prolonged heat treatment.