When do we stop digging? Conditions on a fundamental theory of physics

In seeking an answer to the question of what it means for a theory to be fundamental, it is enlightening to ask why the current best theories of physics are not generally believed to be fundamental. This reveals a set of conditions that a theory of physics must satisfy in order to be considered fundamental. Physics aspires to describe ever deeper levels of reality, which may be without end. Ultimately, at any stage we may not be able to tell whether we've reached rock bottom, or even if there is a base level – nevertheless, I draft a checklist to help us identify when to stop digging, in the case where we may have reached a candidate for a final theory. Given that the list is – according to (current) mainstream belief in high-energy physics – complete, and each criterion well-motivated, I argue that a physical theory that satisfies all the criteria can be assumed to be fundamental in the absence of evidence to the contrary (i.e., I argue that the necessary conditions are jointly sufficient for a claim of fundamentality in physics)

Ubiquitous computing and knowledge management

MOBIlearn is a large European research project to develop a mobile learning system to facilitate formal, non formal and informal learning. The project has two primary objectives: • Develop a methodology for creating mobile learning scenarios and producing learning objects to implement them. • Develop the technology to deliver the learning objects to users via mobile computing devices. This paper will concentrate the MOBIlearn health care domain. One of this applications main objectives is managing and sharing of tacit knowledge. Using the system participants discuss case studies and alternative approaches to specific problems are evaluated and documented. This is then used and extended in future case studies. In a mobile learning environment, individual health workers can use the system to either advanced their skills, or in a ‘live’ incident, use it for reference and indeed call for backup.</p

Out of Control: Patients Are Unwittingly Subjected to Enormous, Unfair, Out-of-Network "Balance Bills"

Excessive medical debt resulting from the provision of health care can cause families and individuals to spend down their savings, forego medical treatment, and even go without paying for food and heat. In the United States, medical bills are the leading cause of individual and family bankruptcy. In 1981, only 8 percent of families filing for bankruptcy protection did so in the aftermath of receiving medical care.However, by 2007, more than 62 percent of all bankruptcies were linked to a medical event, according to a study published in the American Journal of Medicine. And bankruptcy was not limited to the uninsured. To the contrary, the study reported that more than 75 percent of filers had health insurance.One driver of excessive health care bills is a practice known as "balance billing," which refers to bills for the difference between the amount that an insurance company is willing to pay for treatment and a provider's total charges. Providers who are not members of a patient's insurance network have charged patients as much as 9,000 percent of what Medicare would have paid for the same procedure.In contrast, payment for in-network medical services is on average 123 percent of Medicare.Patients can be subjected to balance bills despite making their best efforts to avoid them. For instance, they might receive care at an in-network facility, only to find out later that an out-of-network doctor also provided medical services. This is because many doctors work at hospitals rather than for hospitals, and are not members of the same insurance network as the hospital.Solutions are possible at both the federal and state levels that would protect consumers from balance bills without unduly burdening providers or insurers, or upsetting the existing system of insurance networks. This paper outlines policies that have been implemented at each of these levels and proposes additional protections at the federal level

Inter-theory Relations in Quantum Gravity: Correspondence, Reduction and Emergence

Relationships between current theories, and relationships between current theories and the sought theory of quantum gravity (QG), play an essential role in motivating the need for QG, aiding the search for QG, and defining what would count as QG. Correspondence is the broad class of inter-theory relationships intended to demonstrate the necessary compatibility of two theories whose domains of validity overlap, in the overlap regions. The variety of roles that correspondence plays in the search for QG are illustrated, using examples from specific QG approaches. Reduction is argued to be a special case of correspondence, and to form part of the definition of QG. Finally, the appropriate account of emergence in the context of QG is presented, and compared to conceptions of emergence in the broader philosophy literature. It is argued that, while emergence is likely to hold between QG and general relativity, emergence is not part of the definition of QG, and nor can it serve usefully in the development and justification of the new theory

Fundamental Parameters of Massive Stars

We discuss the determination of fundamental parameters of `normal' hot, massive OB-type stars, namely temperatures, luminosities, masses, gravities and surface abundances. We also present methods used to derive properties of stellar winds -- mass-loss rates and wind velocities from early-type stars.Comment: 21 pages, 3 figures, to appear in "Massive Stars: Formation, Evolution and Environment", eds. Heydari-Malayeri & Zahn (proceedings of 2002 Aussois summer school

A survey of the Wolf-Rayet population of the barred, spiral galaxy NGC 1313

We present a VLT/FORS1 survey of Wolf-Rayet (WR) stars in the spiral galaxy NGC 1313. In total, 94 WR candidate sources have been identified from narrow-band imaging. Of these, 82 have been spectroscopically observed, for which WR emission features are confirmed in 70 cases, one of which also exhibits strong nebular HeII 4686 emission. We also detect strong nebular HeII 4686 emission within two other regions of NGC 1313, one of which is a possible supernova remnant. Nebular properties confirm that NGC 1313 has a metal-content log(O/H)+12=8.23+/-0.06, in good agreement with previous studies. From continuum subtracted Halpha images we infer a global star formation rate of 0.6 Msun/yr. Using template LMC WR stars, spectroscopy reveals that NGC 1313 hosts a minimum of 84 WR stars. Our census comprises 51 WN stars, including a rare WN/C transition star plus 32 WC stars. In addition, we identify one WO star which represents the first such case identified beyond the Local Group. The bright giant HII region PES 1, comparable in Halpha luminosity to NGC 595 in M 33, is found to host a minimum of 17 WR stars. The remaining photometric candidates generally display photometric properties consistent with WN stars, such that we expect a global WR population of ~115 stars with N(WR)/N(O)~0.01 and N(WC)/N(WN)~0.4.Comment: Accepted for publication in MNRAS. Finding charts omitted, full version available by anonymous ftp (ftp: hydra.shef.ac.uk/pub/lh/ngc1313-fullversion.pd