23,931 research outputs found
Dissociative recombination of molecular ions with electrons
An overview is presented for the present state of the art of laboratory measurements of the dissociative recombination of molecular ions with electrons. Most work has focussed on obtaining rates and their temperature dependence, as these are of primary interest for model calculations of ionospheres. A comparison of data obtained using the microwave afterglow method, the flowing afterglow technique, and the merged beam technique shows that generally the agreement is quite good, but there are some serious discrepancies, especially in the case of H(3+) recombination, that need to be resolved. Results of some earlier experimental work need to be reexamined in the light of more recent developments. Such cases are pointed out and a compilation of rate coefficients that have withstood scrutiny is presented. Recent advances in experimental methods, such as the use of laser-in-duced fluorescence, make it possible to identify some neutral products of dissociative recombination. What has been done so far and what results one might expect from future work are briefly reviewed
The Obama Administrationâs Decision to Defend Constitutional Equality Rather Than the Defense of Marriage Act
When President Barack Obama announced his view that the Defense of Marriage Act1 (DOMA) violated the Fifth Amendmentâs guarantee of equal protection,2 he joined a storied line of Presidents who have acted upon their own constitutional determinations in the absence of, and on rare occasion contrary to, those of the U.S. Supreme Court. How best to proceed in the face of a federal statute the President considers unconstitutional can involve complex judgments, as was true of the difficult decision to enforce but not defend DOMA. Ordinarily the Department of Justice should adhere to its tradition of defending statutes against constitutional challenge, but I believe that DOMA constituted a rare exception. To defend DOMAâs discrimination would have required making arguments that the Obama Administration did not consider reasonable and that in their very making would have exacerbated the constitutional harm to the equality and dignity of Americans on the basis of sexual orientation. President Obama and Attorney General Eric Holder acted appropriately and admirably in choosing instead to present their actual views on sexual orientation discrimination, just as their predecessors did on racial segregation, thereby leaving DOMAâs defense to Congress and the ultimate resolution to the courts
Where's the âfaithâ in âfaith-basedâ organisations? The evolution and practice of faith-based homelessness services in the UK
AbstractDrawing upon a qualitative exploration of the role of faith-based organisations (FBOs) in service provision for homeless people in the UK, this paper examines the ways in which the âfaithâ in âfaith-basedâ services is articulated and experienced âon the groundâ. It demonstrates that the âFâ in FBO is expressed in a myriad of nuanced ways, and that the strength of âcouplingâ between many welfare agencies and organised religion has diminished over time such that some projectsâ faith affiliation or heritage is now evident in palimpsest only. Homeless people do in fact often find it difficult to discern tangible differences between avowedly âfaith-basedâ and âsecularâ projects, given a blurring of boundaries between the religious and the secular. These findings problematise FBO typologies, and highlight the complexity and fluidity of the very concept of âFBOâ itself. Certainly, they suggest that the differences between faith-based and secular provision should not be exaggerated, whilst recognising the importance of faith to the motivations of many service providers and the potential value of the (optional) âspiritualâ support offered by most FBOs.</jats:p
Characterisation of Log-Convex Decay in Non-Selfadjoint Dynamics
The short-time and global behaviour are studied for an autonomous linear
evolution equation, which is defined by a generator inducing a uniformly
bounded holomorphic semigroup in a Hilbert space. A general necessary and
sufficient condition is introduced under which the norm of the solution is
shown to be a log-convex and strictly decreasing function of time, and
differentiable also at the initial time with a derivative controlled by the
lower bound of the generator, which moreover is shown to be positively
accretive. Injectivity of holomorphic semigroups is the main technical tool.Comment: 11 pages. Version to appear in Electronic Research Announcements in
Mathematical Sciences (a precision in Lemma 3.2, plus minor improvements
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