444 research outputs found
Moral enhancement: do means matter morally?
One of the reasons why moral enhancement may be controversial, is because the advantages of moral enhancement may fall upon society rather than on those who are enhanced. If directed at individuals with certain counter-moral traits it may have direct societal benefits by lowering immoral behavior and increasing public safety, but it is not directly clear if this also benefits the individual in question. In this paper, we will discuss what we consider to be moral enhancement, how different means may be used to achieve it and whether the means we employ to reach moral enhancement matter morally. Are certain means to achieve moral enhancement wrong in themselves? Are certain means to achieve moral enhancement better than others, and if so, why? More specifically, we will investigate whether the difference between direct and indirect moral enhancement matters morally. Is it the case that indirect means are morally preferable to direct means of moral enhancement and can we indeed pinpoint relevant intrinsic, moral differences between both? We argue that the distinction between direct and indirect means is indeed morally relevant, but only insofar as it tracks an underlying distinction between active and passive interventions. Although passive interventions can be ethical provided specific safeguards are put in place, these interventions exhibit a greater potential to compromise autonomy and disrupt identity
The narrative self, distributed memory, and evocative objects
In this article, I outline various ways in which artifacts are interwoven with autobiographical memory systems and conceptualize what this implies for the self. I first sketch the narrative approach to the self, arguing that who we are as persons is essentially our (unfolding) life story, which, in turn, determines our present beliefs and desires, but also directs our future goals and actions. I then argue that our autobiographical memory is partly anchored in our embodied interactions with an ecology of artifacts in our environment. Lifelogs, photos, videos, journals, diaries, souvenirs, jewelry, books, works of art, and many other meaningful objects trigger and sometimes constitute emotionally-laden autobiographical memories. Autobiographical memory is thus distributed across embodied agents and various environmental structures. To defend this claim, I draw on and integrate distributed cognition theory and empirical research in human-technology interaction. Based on this, I conclude that the self is neither defined by psychological states realized by the brain nor by biological states realized by the organism, but should be seen as a distributed and relational construct
Cell transformation assays for prediction of carcinogenic potential: State of the science and future research needs
Copyright @ 2011 The Authors. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits
unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.Cell transformation assays (CTAs) have long been proposed as in vitro methods for the identification of potential chemical carcinogens. Despite showing good correlation with rodent bioassay data, concerns over the subjective nature of using morphological criteria for identifying transformed cells and a lack of understanding of the mechanistic basis of the assays has limited their acceptance for regulatory purposes. However, recent drivers to find alternative carcinogenicity assessment methodologies, such as the Seventh Amendment to the EU Cosmetics Directive, have fuelled renewed interest in CTAs. Research is currently ongoing to improve the objectivity of the assays, reveal the underlying molecular changes leading to transformation and explore the use of novel cell types. The UK NC3Rs held an international workshop in November 2010 to review the current state of the art in this field and provide directions for future research. This paper outlines the key points highlighted at this meeting
Interplay between quasi-periodicity and disorder in quantum spin chains in a magnetic field
We study the interplay between disorder and a quasi periodic coupling array
in an external magnetic field in a spin-1/2 XXZ chain. A simple real space
decimation argument is used to estimate the magnetization values where plateaux
show up. The latter are in good agreement with exact diagonalization results on
fairly long XX chains. Spontaneous susceptibility properties are also studied,
finding a logarithmic behaviour similar to the homogeneously disordered case.Comment: 5 RevTeX pages, 5 Postscript figures include
Hirzebruch-Milnor classes and Steenbrink spectra of certain projective hypersurfaces
We show that the Hirzebruch-Milnor class of a projective hypersurface, which
gives the difference between the Hirzebruch class and the virtual one, can be
calculated by using the Steenbrink spectra of local defining functions of the
hypersurface if certain good conditions are satisfied, e.g. in the case of
projective hyperplane arrangements, where we can give a more explicit formula.
This is a natural continuation of our previous paper on the Hirzebruch-Milnor
classes of complete intersections.Comment: 15 pages, Introduction is modifie
Gaudin model and its associated Knizhnik-Zamolodchikov equation
The semiclassical limit of the algebraic Bethe Ansatz for the Izergin-Korepin
19-vertex model is used to solve the theory of Gaudin models associated with
the twisted R-matrix. We find the spectra and eigenvectors of the
independents Gaudin Hamiltonians. We also use the off-shell Bethe Ansatz
method to show how the off-shell Gaudin equation solves the associated
trigonometric system of Knizhnik-Zamolodchikov equations.Comment: 20 pages,no figure, typos corrected, LaTe
Therapeutic end points for the treatment of atrioventricular node reentrant tachycardia by catheter-guided radiofrequency current
AbstractObjectives. The purpose off this prospective study was to test the hypothesis that the elimination of inducible repetitive atrioventricular (AV) node reentry the persistence of slow AV pathway conduction is a valid end point for radiofrequency catheter ablation procedures in patients with supraventricular tachycardia due to AV node reentry.Background. Although modification of AV node physiology by radiofrequency current can eliminate AV node reentrant tachycardia, therapeutic end points that are definitive of a satisfactory result in patients undergoing modification of the slow AV pathway have not been established. Applications of radiofrequency current at selected sites may eliminate all evidence of slow pathway conduction or sufficiently modify the refractory properties of the slow pathway to preclude sustained arrhythmias. Accordingly, total abolition of dual AV node physiology may not be necessary to prevent arrhythmia recurrence.Methods. Radiofrequency catheter ablation of the slow AV pathway was attempted in 59 patients with typical AV node reentry. Tissue ablation was performed with a continuous wave of 500-kHz radiofrequency current. Twenty-five to 35 W was applied for 60 s at the site selected for destruction.Results. Dual AV node physiology was eliminated completely in 35 patients (59%), persisted without inducible AV node reentry in 13 patients (22%) and persisted with inducible single AV reentrant beats in 11 patients (19%). In patients with persistent dual AV node physiology, the maximal difference between the effective refractory period of the fast and slow pathways was reduced from 104 ± 62 ms before the procedure to 37 ± 37 ms after AV conduction had been modified (p < 0.001). During a mean follow-up interval of 15 months (range 4 to 28), only one patient (2%) had a recurrence of the tachycardia.Conclusions. Resulte demonstrate that when complete elimination of dial AV node physiology is difficult, modification of slow pathway conduction to the extent that repetitive AV node reentry cannot be induced is a definitive end point that portends a good prognosis
A millisecond pulsar in a stellar triple system
Gravitationally bound three-body systems have been studied for hundreds of
years and are common in our Galaxy. They show complex orbital interactions,
which can constrain the compositions, masses, and interior structures of the
bodies and test theories of gravity, if sufficiently precise measurements are
available. A triple system containing a radio pulsar could provide such
measurements, but the only previously known such system, B1620-26 (with a
millisecond pulsar, a white dwarf, and a planetary-mass object in an orbit of
several decades), shows only weak interactions. Here we report precision timing
and multi-wavelength observations of PSR J0337+1715, a millisecond pulsar in a
hierarchical triple system with two other stars. Strong gravitational
interactions are apparent and provide the masses of the pulsar (1.4378(13)
Msun, where Msun is the solar mass and the parentheses contain the uncertainty
in the final decimal places) and the two white dwarf companions (0.19751(15)
Msun and 0.4101(3) Msun), as well as the inclinations of the orbits (both
approximately 39.2 degrees). The unexpectedly coplanar and nearly circular
orbits indicate a complex and exotic evolutionary past that differs from those
of known stellar systems. The gravitational field of the outer white dwarf
strongly accelerates the inner binary containing the neutron star, and the
system will thus provide an ideal laboratory in which to test the strong
equivalence principle of general relativity.Comment: 17 pages, 3 figures, 1 table. Published online by Nature on 5 Jan
2014. Extremely minor differences with published version may exis
Surface Magnetization and Critical Behavior of Aperiodic Ising Quantum Chains
We consider semi-infinite two-dimensional layered Ising models in the extreme
anisotropic limit with an aperiodic modulation of the couplings. Using
substitution rules to generate the aperiodic sequences, we derive functional
equations for the surface magnetization. These equations are solved by
iteration and the surface magnetic exponent can be determined exactly. The
method is applied to three specific aperiodic sequences, which represent
different types of perturbation, according to a relevance-irrelevance
criterion. On the Thue-Morse lattice, for which the modulation is an irrelevant
perturbation, the surface magnetization vanishes with a square root
singularity, like in the homogeneous lattice. For the period-doubling sequence,
the perturbation is marginal and the surface magnetic exponent varies
continuously with the modulation amplitude. Finally, the Rudin-Shapiro
sequence, which corresponds to the relevant case, displays an anomalous surface
critical behavior which is analyzed via scaling considerations: Depending on
the value of the modulation, the surface magnetization either vanishes with an
essential singularity or remains finite at the bulk critical point, i.e., the
surface phase transition is of first order.Comment: 8 pages, 7 eps-figures, uses RevTex and epsf, minor correction
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