Traveling-wave solutions of the standard and compound form of Korteweg–de Vries–Burgers equations are found using factorizations of the corresponding reduced ordinary differential equations. The procedure leads to solutions of Bernoulli equations of non-linearity 3/2 and 2 (Riccati), respectively. Introducing the initial conditions through an imaginary phase in the traveling coordinate, we obtain all the solutions previously reported, some of them being corrected here, and showing, at the same time, the presence of interesting details of these solitary waves that have been (...) overlooked before this investigation. (shrink)

The requirement of gauge invariance for the Schwinger-DeWitt equations, interpreted as a manifestly covariant quantum theory for the evolution of a system in spacetime, implies the existence of a five-dimensional pre-Maxwell field on the manifold of spacetime and “proper time” τ. The Maxwell theory is contained in this theory; integration of the field equations over τ restores the Maxwell equations with the usual interpretation of the sources. Following Schwinger's techniques, we study the Green's functions for the five-dimensional hyperbolic field equations (...) for both signatures ± [corresponding to O(4, 1) or O(3, 2) symmetry of the field equations] of the proper time derivative. The classification of the Green's functions follows that of the four-dimensional theory for “massive” fields, for which the “mass” squared may be positive or negative, respectively. The Green's functions for the five-dimensional field are then given by the Fourier transform over the “mass” parameter. We derive the Green's functions corresponding to the principal part ΔP and the homogeneous function Δ 1 ; all of the Green's functions can be expressed in terms of these, as for the usual field equations with definite mass. In the O(3, 2) case, the principal part function has support for x2⩾τ2, corresponding to spacelike propagation, as well as along the light cone x2=0 (for τ=0). There can be no transmission ofinformation in spacelike directions, with this propagator, since the Maxwell field, obtained by integration over τ, does not contain this component of the support. Measurements are characterized by such an integration. The spacelike field therefore can dynamically establish spacelike correlations. (shrink)

There is ongoing ethical and legal debate about withdrawing life sup- port for patients with disorders of consciousness (DOCs). Frequently fu- eling the debate are implicit assumptions about the value of life in a state of impaired consciousness, and persistent uncertainty about the quality of life (QoL) of these persons. Yet there are no validated methods for assessing QoL in this population, and a significant obstacle to doing so is their inability to communicate. Recent neuroscientific discoveries might circumvent that problem (...) and help shed light on QoL in DOCs. There is an ethical imperative to prioritize QoL research in this patient population, to provide evidence to inform treatment, research, and end of life decisions. A minimalist and pragmatic model of QoL is proposed, targeting positive and negative affect as domains for which there is po- tential to reach across the communication gap, and restore to these voiceless persons some measure of control. (shrink)

Recent discussions of experimental tests of the Sum Rule have been carried out in the context of the special circumstances attending the Cross-Ramsey experiment. A more general analysis of possible tests is presented. A technical mistake of Fine and Glymour concerned with a misunderstanding of the physics of the Cross-Ramsey experiment is explained and a detailed analysis of a thought experiment based on the Einstein-Podolsky-Rosen wave function is given. It is concluded, in agreement with Fine, that scattering experiments do not (...) test the Sum Rule as a principle which supplements standard quantum mechanics. (shrink)

Bioethics is best viewed as both a second-order discipline and also part of public discourse. Since their goals differ, some bioethical activities are more usefully viewed as advancing public discourse than academic disciplines. For example, the “Universal Declaration on Bioethics and Human Rights” sponsored by the United Nations Educational, Scientific, and Cultural Organization seeks to promote ethical guidance on bioethical issues. From the vantage of philosophical ethics, it fails to rank or specify its stated principles, justify controversial principles, clarify key (...) terms, or say what is meant by calling potentially conflicting norms “foundational.” From the vantage of improving the public discourse about bioethical problems and seeking ethical solutions in the public arena, however, this document may have an important role. The goals and relations between bioethics as a second-order discipline and public discourse are explored. (shrink)

Pickering & Garrod's (P&G's) integrated model of production and comprehension includes no explicit role for nonlinguistic cognitive processes. Yet, how domain-general cognitive functions contribute to language processing has become clearer with well-specified theories and supporting data. We therefore believe that their account can benefit by incorporating functions like working memory and cognitive control into a unified model of language processing.

What if human joy went on endlessly? Suppose, for example, that each human generation were followed by another, or that the Western religions are right when they teach that each human being lives eternally after death. If any such possibility is true in the actual world, then an agent might sometimes be so situated that more than one course of action would produce an infinite amount of utility. Deciding whether to have a child born this year rather than next is (...) a situation wherein an agent may face several alternatives whose effects could well ramify endlessly on such suppositions, for the child born this year would be a different person—one who preferred different things, performed different actions, and had different descendants—from a child born next year. It has recently been suggested that traditional utilitarianism stumbles on such cases of infinite utility. Specifically, utilitarianism seems to require, for its application, that all experience of pleasure and pain cease at some time in the future or asymptotically approach zero.2 If neither of these conditions holds, then the utility produced by each of two alternative actions may turn out to be infinite, and utilitarianism thus loses its ability to discriminate morally between them. (shrink)

The phenomenon whereby severely disabled persons self-report a higher than expected level of subjective well-being is called the “disability paradox.” One explanation for the paradox among brain injury survivors is “response shift,” an adjustment of one’s values, expectations, and perspective in the aftermath of a life-altering, disabling injury. The high level of subjective well-being appears paradoxical when viewed from the perspective of the non-disabled, who presume that those with severe disabilities experience a quality of life so poor that it might (...) make their lives not worth living. This presumption has profound consequences, for it may inform end-of-life choices made in advance directives, or influence decisions made by surrogates on behalf of persons who are unable to direct their own medical treatment. -/- Peterson et al propose a cautious, well-considered plan to use fMRI-based brain-computer interfaces to assess the decision making capacity of covertly aware, behaviorally non-responsive individuals who retain high levels of preserved cognition. Their plan, if it succeeds, could eventually restore autonomy and empower some severely disabled persons, allowing them to participate in clinical decision making. Peterson et al discuss possible in-principle objections to their proposal, among them the “argument from psychological health,” and the “changing sets of values” objection. These objections both presume that deviations from a pre-injury norm could indicate diminished decision making capacity. This presumption threatens the autonomy of the patient who is capable of making decisions, but whose post-injury decisions appear to diverge from pre-injury preferences or values. In light of the potential for response shift, and the disability paradox, it should not be inferred that changes in values or preferences are unreflective of the true current preferences of a brain-injured person, nor are they conclusive evidence of diminished capacity. Presuming diminished capacity on the basis of unexpected or unconventional preferences has, in the past, been used to disempower patients whose autonomy and capacity would not have been doubted had they made choices that accorded with the expectations or values of others. We must be cautious, and vigilant, to prevent similarly diminishing the autonomy of covertly aware, behaviorally non-responsive individuals on the basis of empirically and ethically questionable inferences about their decision making capacity. (shrink)

The problem of the electromagnetic coupling for spin-3/2 particles is discussed. Following supergravity and some previous researches in the field of classical supersymmetric particles, we found that the electromagnetic coupling must not obey a minimal coupling in the sense of coupling the electromagnetic potential, but some kind of an electromagnetic field strength.

One of the most tantalizing questions about the interpretation of Quantum Theory is the objective vs. subjective meaning of quantum states. Here, by focusing on a typical EPR experiment upon which a selection procedure is performed on one side, we will confront the fully epistemic view of quantum states with its results. Our statement is that such a view cannot be considered complete, although the opposite attitude would also pose well-known problems of interpretation.

Recalcitrant disputes among health care providers and patients or their families may signal deep cultural differences about what interventions are needed or about clinicians’s professional duties. These issues arose in relation to a mother’s request for hymenoplasty or revirgination for her minor daughter to enable an overseas, forced marriage and protect her from an honor killing. The American College of Obstetrics and Gynecology committee recommends against members performing a hymenoplasty or other female genital cosmetic surgeries due to a lack of (...) data concerning their safety and efficacy. A key issue in such cases is how to determine what is in the minor’s best interest and the scope of health care moral or professional’s duties. The Best Interests Standard can serve as a powerful moral tool for resolving cross-cultural disputes and identifying needed policy. (shrink)

Many years ago, when Michael was lecturing in Oxford on the Philosophy of Physics and was trying to explain the logic of Aspect's experiments in Paris, he turned to me to expound the correct doctrine of counter-factual truth. I was flummoxed. It had been much discussed in late- and postmediaeval times, especially in the Iberian peninsula, and had recently enjoyed a revival in the Eastern United States. But Middle Knowledge, as the Schoolmen called it, was beyond my comprehension, and I (...) could only exemplify once again the truism that philosophers were better at raising problems than resolving them. (shrink)