4,657 research outputs found
A pedagogic appraisal of the Priority Heuristic
We have explored how science and mathematics teachers made decisions when confronted with a dilemma in which a fictitious young woman, Deborah, may choose to have an operation that might address a painful spinal condition. We sought to explore the extent to which psychological heuristic models, in particular the Priority Heuristic, might successfully describe the decision-making process of these teachers and how an analysis of the role of personal and emotional factors in shaping the decision-making process might inform pedagogical design. A novel aspect of this study is that the setting in which the decision-making process is examined contrasts sharply with those used in psychological experiments. We found that to some extent, even in this contrasting setting, the Priority Heuristic could describe these teachers' decision-making. Further analysis of the transcripts yielded some insights into limitations on scope as well the richness and complexity in how personal factors were brought to bear. We see these limitations as design opportunities for educational intervention
Advance care planning in patients with incurable cancer: Study protocol for a randomised controlled trial
Introduction: There is limited evidence documenting the effectiveness of Advance Care Planning (ACP) in cancer care. The present randomised trial is designed to evaluate whether the administration of formal ACP improves compliance with patients' end-of-life (EOL) wishes and patient and family satisfaction with care. Methods and analysis: A randomised control trial in eight oncology centres across New South Wales and Victoria, Australia, is designed to assess the efficacy of a formal ACP intervention for patients with cancer. Patients with incurable cancer and an expected survival of 3-12 months, plus a nominated family member or friend will be randomised to receive either standard care or standard care plus a formal ACP intervention. The project sample size is 210 patient-family/friend dyads. The primary outcome measure is family/friendreported: (1) discussion with the patient about their EOL wishes and (2) perception that the patient's EOL wishes were met. Secondary outcome measures include: documentation of and compliance with patient preferences for medical intervention at the EOL; the family/friend's perception of the quality of the patient's EOL care; the impact of death on surviving family; patient-family and patient-healthcare provider communication about EOL care; patient and family/ friend satisfaction with care; quality of life of patient and family/friend subsequent to trial entry, the patient's strength of preferences for quality of life and length of life; the costs of care subsequent to trial entry and place of death. Ethics and dissemination: Ethical approval was received from the Sydney Local Health District (RPA Zone) Human Research Ethical Committee, Australia (Protocol number X13-0064). Study results will be submitted for publication in peer-reviewed journals and presented at national and international conferences. Trial registration number: Pre-results; ACTRN12613001288718
Search for the evidence of endocrine disruption in the aquatic environment: Lessons to be learned from joint biological and chemical monitoring in the European Project COMPREHEND
Between January 1999 and December 2001, the European Community project COMPREHEND was performed. The overall aim of COMPREHEND was to assess endocrine disruption in the aquatic environment in Europe, consequent to effluent discharge, with emphasis on estrogenic activity. COMPREHEND demonstrated the widespread occurrence of estrogenic effluents across Europe and presented evidence of impacts on a range of wild fish species. Using a variety of bioassays in combination with chemical analytical methods, estrogenic steroids of human origin from domestic wastewater effluents were identified as the most pervasive problem, although alkylphenols may be important estrogenic components of some industrial effluents. New tools have been developed for the identification of estrogenic effluents, and recommendations are made for the improvement of existing techniques. We have shown that individual fish within natural populations may be feminized to varying degrees, but it has not been possible to show, using traditional fish population parameters, that the survival of fish populations is threatened. However, laboratory-based fish life-cycle studies demonstrate the sensitivity of fish to estrogen (and androgen) exposure and how this might lead to complex (and potentially damaging) genetic changes at the population level. New approaches to this problem, utilizing recent advances made in the field of molecular and population genetics, are recommended. Finally, a study of estrogenic and androgenic activity of waste waters during the treatment process has shown that some of the existing wastewater treatment technologies have the potential to eliminate or minimize the hormonal activity of the final effluent
Perturbations of nuclear C*-algebras
Kadison and Kastler introduced a natural metric on the collection of all
C*-subalgebras of the bounded operators on a separable Hilbert space. They
conjectured that sufficiently close algebras are unitarily conjugate. We
establish this conjecture when one algebra is separable and nuclear. We also
consider one-sided versions of these notions, and we obtain embeddings from
certain near inclusions involving separable nuclear C*-algebras. At the end of
the paper we demonstrate how our methods lead to improved characterisations of
some of the types of algebras that are of current interest in the
classification programme.Comment: 45 page
Widespread active detachment faulting and core complex formation near 13°N on the Mid-Atlantic Ridge
Author Posting. © Nature Publishing Group, 2006. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 442 (2006): 440-443, doi:10.1038/nature04950.Oceanic core complexes are massifs in which lower crustal and upper mantle rocks are exposed at the sea floor. They form at mid-ocean ridges through slip on detachment faults rooted below the spreading axis. To date, most studies of core complexes have been based on isolated inactive massifs that have spread away from ridge axes. A new survey of the Mid-Atlantic Ridge (MAR) near 13°N reveals a segment in which a number of linked detachment faults extend for 75 km along one flank of the spreading axis. The detachment faults are apparently all currently active and at various stages of development. A field of extinct core complexes extends away from the axis for at least 100 km. The new data document the topographic characteristics of actively-forming core complexes and their evolution from initiation within the axial valley floor to maturity and eventual inactivity. Within the surrounding region there is a strong correlation between detachment fault morphology at the ridge axis and high rates of hydroacoustically-recorded earthquake seismicity. Preliminary examination of seismicity and seafloor morphology farther north along the MAR suggests that active detachment faulting is occurring in many segments and that detachment faulting is more important in the generation of ocean crust at this slow-spreading ridge than previously suspected.This work was supported by the National Science Foundation
Casimir effect due to a single boundary as a manifestation of the Weyl problem
The Casimir self-energy of a boundary is ultraviolet-divergent. In many cases
the divergences can be eliminated by methods such as zeta-function
regularization or through physical arguments (ultraviolet transparency of the
boundary would provide a cutoff). Using the example of a massless scalar field
theory with a single Dirichlet boundary we explore the relationship between
such approaches, with the goal of better understanding the origin of the
divergences. We are guided by the insight due to Dowker and Kennedy (1978) and
Deutsch and Candelas (1979), that the divergences represent measurable effects
that can be interpreted with the aid of the theory of the asymptotic
distribution of eigenvalues of the Laplacian discussed by Weyl. In many cases
the Casimir self-energy is the sum of cutoff-dependent (Weyl) terms having
geometrical origin, and an "intrinsic" term that is independent of the cutoff.
The Weyl terms make a measurable contribution to the physical situation even
when regularization methods succeed in isolating the intrinsic part.
Regularization methods fail when the Weyl terms and intrinsic parts of the
Casimir effect cannot be clearly separated. Specifically, we demonstrate that
the Casimir self-energy of a smooth boundary in two dimensions is a sum of two
Weyl terms (exhibiting quadratic and logarithmic cutoff dependence), a
geometrical term that is independent of cutoff, and a non-geometrical intrinsic
term. As by-products we resolve the puzzle of the divergent Casimir force on a
ring and correct the sign of the coefficient of linear tension of the Dirichlet
line predicted in earlier treatments.Comment: 13 pages, 1 figure, minor changes to the text, extra references
added, version to be published in J. Phys.
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