Einstein metrics in projective geometry

It is well known that pseudo-Riemannian metrics in the projective class of a given torsion free affine connection can be obtained from (and are equivalent to) the solutions of a certain overdetermined projectively invariant differential equation. This equation is a special case of a so-called first BGG equation. The general theory of such equations singles out a subclass of so-called normal solutions. We prove that non-degerate normal solutions are equivalent to pseudo-Riemannian Einstein metrics in the projective class and observe that this connects to natural projective extensions of the Einstein condition.Comment: 10 pages. Adapted to published version. In addition corrected a minor sign erro

Performance measurement of cross-culture supply chain partnership: a case study in the Chinese automotive industry

This study explores a performance measurement system for a dynamic supply chain partnership in a cross-cultural context. An initial framework is constructed by reviewing the existing literature, followed by an in-depth case study in the Chinese automotive industry, where the framework is refined to address the multi-cultural setting. A performance measurement, system which includes the relationship strategy and operational measurement criteria for a supply chain partnership, has been developed. The relationship strategy contains elements of strategy orientation, management style, interdependence, mutual organisational characteristics and common goals. The operational measurement criteria consist of commitment, trust, communication behaviour, information sharing, participation decision, quality, production performance, delivery, cost, supplier strength, attitude, compromise and loyalty. The last three operational measurement criteria are found to be particularly relevant to the cross-cultural feature. While existing studies tend to focus on either specific measures or individual organisations, this paper for the first time proposes a comprehensive framework to measure the performance of supply chain partnerships. The cross-cultural perspective provides a further unique view on how a performance measurement system can be responsive to the dynamics in practice

Policy, Performativity and Partnership: an Ethical Leadership Perspective

This article identifies the need to think differently about educational partnerships in a changing and turbulent post compulsory policy environment in England. The policy and institutional contexts in which universities and colleges currently operate seem to be fuelling performativity at the expense of educational values. There appears to be a sharp interruption in the steady increase in educational partnerships as a vehicle for increasing and widening participation in higher education. We are witnessing a marked change in university / college relationships that appears to be a consequence of government calling a halt to increased participation in higher education, creating an increasingly competitive market for a more limited pool of student places. The implication that educational policy at the national level determines a particular pattern or mode of leadership decision making throughout an institution should however be resisted. Policy developments that challenge the moral precepts of education should not be allowed to determine how a leader acts, rather they should prompt actions that are truly educational, rooted in morality, and atached to identifiable educational values. Educational leaders have agency to resist restricted discourses in favour of ethical and principled change strategies that are a precondition for sustainable transformative partnerships in post compulsory education. University leaders in particular are called upon to use their considerable influence to resist narrow policy or managerial instrumentalism or performativity and embrace alternatives that are both educationally worthwhile and can enhance institutional resilience

Long Type I X-ray Bursts and Neutron Star Interior Physics

Superbursts are very energetic Type I X-ray bursts discovered in recent years by long term monitoring of X-ray bursters, believed to be due to unstable ignition of carbon in the deep ocean of the neutron star. A number of "intermediate duration" bursts have also been observed, probably associated with ignition of a thick helium layer. We investigate the sensitivity of these long X-ray bursts to the thermal profile of the neutron star crust and core. We first compare cooling models of superburst lightcurves with observations, and derive constraints on the ignition mass and energy release, and then calculate ignition models for superbursts and pure helium bursts, and compare to observations. The superburst lightcurves and ignition models imply that the carbon mass fraction is approximately 20% or greater in the fuel layer, constraining models of carbon production. However, the most important result is that when Cooper pairing neutrino emission is included in the crust, the temperature is too low to support unstable carbon ignition at the observed column depths. Some additional heating mechanism is required in the accumulating fuel layer to explain the observed properties of superbursts. If Cooper pair emission is less efficient than currently thought, the observed ignition depths for superbursts imply that the crust is a poor conductor, and the core neutrino emission is not more efficient than modified URCA. The observed properties of helium bursts support these conclusions, requiring inefficient crust conductivity and core neutrino emission.Comment: submitted to ApJ (22 pages, 26 figures

Reports of the AAAI 2019 spring symposium series

Applications of machine learning combined with AI algorithms have propelled unprecedented economic disruptions across diverse fields in industry, military, medicine, finance, and others. With the forecast for even larger impacts, the present economic impact of machine learning is estimated in the trillions of dollars. But as autonomous machines become ubiquitous, recent problems have surfaced. Early on, and again in 2018, Judea Pearl warned AI scientists they must "build machines that make sense of what goes on in their environment," a warning still unheeded that may impede future development. For example, self-driving vehicles often rely on sparse data; self-driving cars have already been involved in fatalities, including a pedestrian; and yet machine learning is unable to explain the contexts within which it operates

Self reported skin morbidity and ethnicity: a population-based study in a Western community

<p>Abstract</p> <p>Background</p> <p>Recent studies have shown ethnic differences concerning cardio-vascular disease, diabetes and mental health. Little is known about ethnic differences in skin morbidity. The purpose of this study was to describe possible ethnic differences in self-reported skin morbidity in a Western urban community.</p> <p>Methods</p> <p>The design was cross sectional. 40 888 adults in Oslo, Norway, received a postal questionnaire providing information on socio-demographic factors and self-reported health, including items on skin complaints.</p> <p>Results</p> <p>18770 individuals answered the questionnaire. In the sample 84% were from Norway. The largest immigrant group was from Western countries (5%) and the Indian Subcontinent (3%). Itch was the most prevalent reported skin symptom (7%), and was significantly more reported by men from East Asia (18%) and Middle East/North Africa (13%). The same observations were seen for reported dry and sore skin. Hair loss was a dominating complaint for men from the Indian Subcontinent and the Middle East/North Africa (23% and 25%) and for women from the same ethnic groups. Women from Sub-Saharan Africa reported significantly more pimples than in the other groups (17%).</p> <p>Conclusion</p> <p>The study showed that there were significant differences in self-reported skin complaints among ethnic groups. Issues concerning the cultural value of some skin symptoms should be examined further.</p

Tourism Partnerships in Protected Areas: Exploring Contributions to Sustainability

Partnerships between natural-area managers and the tourism industry have been suggested to contribute to sustainability in protected areas. This article explores how important sustainability outcomes of partnerships are to their members, how well they are realised and the features of partnerships leading to their achievement. In 21 case studies in Australia, interviews (n = 97) and surveys (n = 100) showed that of 14 sustainability outcomes, improved understanding of protected areas values and improved biodiversity conservation were the most important. Other highly ranked outcomes were greater respect for culture, heritage, and/or traditions; improved quality of environmental conditions; social benefits to local communities; and improved economic viability of the protected area. Scores for satisfaction with outcomes were, like those for importance, all high but were less than those for importance for the majority, with improvement in quality of environmental conditions showing the largest gap. The satisfaction score exceeded that for importance only for increased competitiveness of the protected area as a tourist destination. “Brown” aspects of sustainability, i.e., decreased waste or energy use, were among the lowest-scoring outcomes for both importance and satisfaction. The most important factor enabling sustainability outcomes was provision of benefits to partnership members. Others were increased financial support, inclusiveness, supportive organisational and administrative arrangements, direct involvement of decision makers, partnership maturity, creation of new relationships, decreased conflict, and stimulation of innovation. Improving sustainability outcomes, therefore, requires maintaining these partnership attributes and also increasing emphasis on reducing waste and resource use

Closing seminars and lectures: The work that lecturers and students do

This paper was accepted for publication in the journal Discourse Studies and the definitive published version is available at https://doi.org/10.1177/1461445617701992Based on an analysis of naturally occurring interactions between lecturers and students, this article investigates how university lectures and seminars are brought to a close through the collaborative work of lecturers and students. The analysis focuses on: firstly, the resources that lecturers and students have to accomplish this (which do not just include speech, but also embodied conduct, as well as references to clock time and lesson phases); secondly, the active role that students play, who may engage in closing activities in ways that attempt to preserve the classroom order (e.g., by packing up silently while continuing to demonstrably listen) or in ways that are disruptive of it (e.g., by packing up noisily); thirdly, the occasional subversive role that students may adopt, who may attempt to initiate closings in order to cut the lecture or seminar short (e.g., by suggesting to the lecturer that he or she is going over time or by engaging in ‘premature’ closing activities)

Review Section : Nature/Nurture Revisited I

Biologically oriented approaches to the study of human conflict have thus far been limited largely to the study of aggression. A sample of the literature on this topic is reviewed, drawing upon four major approaches: comparative psychology, ethology (including some popularized accounts), evolutionary-based theories, and several areas of human physiology. More sophisticated relationships between so-called "innate" and "acquired" determinants of behavior are discussed, along with the proper relevance of animal behavior studies for human behavior. Unless contained in a comprehensive theory which includes social and psychological variables, biolog ically oriented theories (although often valid within their domain) offer at best severely limited and at worst highly misleading explanations of complex social conflicts. The review concludes with a list of several positive contributions of these biological approaches and suggests that social scientists must become more knowledgeable about them.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68270/2/10.1177_002200277401800206.pd