How degenerate can cosmological neutrinos be?

There are well-known bounds on light neutrino masses from cosmological energy density arguments. These arguments assume the neutrinos to be non-degenerate. We show how these bounds are affected if the neutrinos are degenerate. In this case, we obtain correlated bounds between neutrino mass and degeneracy.Comment: 5 pages, Latex, uses epsf.sty. (Some details added at the referee's request. One reference added.

Purely electromagnetic spacetimes

Electrovacuum solutions devoid of usual mass sources are classified in the case of one, two and three commuting Killing vectors. Three branches of solutions exist. Electromagnetically induced mass terms appear in some of them.Comment: 8 page

Wormholes in spacetime with torsion

Analytical wormhole solutions in $U_4$ theory are presented. It is discussed whether the extremely short range repulsive forces, related to the spin angular momentum of matter, could be the ``carrier'' of the exoticity that threads the wormhole throat.Comment: 10 pages revte

The Deep Structure of Law and Morality

This Article argues that morality and law share a deep and pervasive structure, an analogue of what Noam Chomsky calls the “deep structure” of language. This structure arises not to resolve linguistic problems of generativity, but rather from the fact that morality and law engage psychological adaptations with the same natural function: to allow us to resolve social contract problems flexibly. Drawing on and extending a number of contemporary insights from evolutionary psychology and evolutionary game theory, this Article argues that we resolve these problems by employing a particular class of psychological attitudes, which are neither simply belief-like states nor simply desire-like states, though they bear affinities to both. The attitudes are “obligata.” Obligata breathe life into our moral and legal practices, and have a specific structure. They blend agent-centered attitudes toward persons with attitudes toward shared standards for action as producing reasons that exclude some arising from personal interest. Obligata are “judgment-sensitive attitudes”: reasons can be sensibly asked and offered for them. They incline us to react critically to deviations and perceive these reactions as warranted. Obligata nevertheless sensitize us to the standard excuses, thereby allowing us to mend our relationships after some seeming breaches. We express obligata in the special normative terminology that morality and law share, including in contexts of discussion and dispute that can become incredibly charged. In these interactions, obligata allow us to meaningfully disagree, and sometimes thereby reach consensus, even when our resolutions are not traceable to any particular reasons we antecedently accepted. This talk thus engages underlying psychosocial mechanisms that can—in the appropriate social and political circumstances—help us maintain sufficient agreement over what we owe to one another to live well together. Obligata thereby allow us to enjoy our lives together. Finally, it is possible that our moral and legal judgments supervene on natural facts because there are natural facts—about what moral and legal rules would conduce to all our objective individual interests in the right way—that partly explain the shape that morality and law take in our lives. The structure of obligata is the deep structure of morality and law. This suggests that much of the legal literature—including familiar descriptive and normative accounts from law and economics scholars—have been presupposing a psychological picture that is deeply at odds with how we naturally think about obligation. Morality and law do not arise from, and could not be sustained only by, separable beliefs about the world and preferences for states of affairs. The challenge raised here runs deeper, however, than recent empirical work showing we deviate from instrumental rationality in numerous, systematic ways. Our capacities to reason instrumentally may not figure very centrally at all in our moral or legal practices, and we may necessarily misunderstand these normative phenomena if we keep trying to shoehorn them into that model. To understand morality and law, we must instead understand how our distinctive capacities to identify and respond appropriately to obligations function

How and Understanding of the Second Personal Standpoint Can Change Our Understanding of the Law: Hart\u27s Unpublished Response to Exclusive Legal Positivism

This Article describes recent developments in moral philosophy on the “second personal standpoint,” and argues that they will have important ramifications for legal thought. Moral, legal and political thinkers have, for some time now, understood important distinctions between the first personal perspective (of deliberation) and the third personal perspective (of observation, cause and effect), and have plumbed these distinctions to great effect in their thought. This distinction is, in fact, implicit the law and economics movement’s “rational actor” model of decision, which currently dominates much legal academic thought. Recent developments in value theory due to philosopher Stephen Darwall suggest, however, that there is another distinct and irreducible standpoint that we commonly employ in our social interactions: the second personal standpoint. This is the standpoint from which we address one another with claims and grievances, or respond to such claims with apology, excuse or justification. The standpoint employs a distinctive grammatical person, which is as old as our specifically-human capacities for language, and which allows us to ask and answer a distinctive class of practical problems. These are inherently relational problems, which concern how to navigate, manage, repair—and sometimes dissolve—important human relationships. This Article begins by identifying distinctive features of the second personal standpoint. It then illustrates the potential reach of these new developments for legal theory with three examples. Specifically, these developments might help us better diagnose problems that a number of other legal theorists have recently been raising, including, (1) the potential loss involved with silencing criminal defendants (Natapoff), (2) the potential loss inherent in moving from traditional common law uses of precedent to more formalistic approaches (Tiersma), and (3) the inability of economic theories to capture important aspects of tort law’s duty of care (Coleman, Perry, Weinrib). The Article then turns to its central thesis, which is stated in deliberately provocative terms: these new developments will allow us to decipher Hart’s undeveloped but inchoately understood response to exclusive legal positivism, thereby clarifying important aspects of the genuine relationship between law and morality. According to received views, Hart involved himself in inconsistency when he absorbed Raz’s important observations about legal authority into his own jurisprudence. This Article argues, to the contrary, that Hart sensed there was no genuine inconsistency, and for roughly the right reasons. What Hart lacked—and what we have all lacked until now—is a clear account of the second personal standpoint in order to develop and articulate this sense. Using contemporary work, this Article develops a more robust account of legal authority and legal obligation, and defends it against concerns raised by Raz and Shapiro. It argues that Hart would (or at least should) have acknowledged this account as an appropriate elaboration of his views, and as representing the best available framework from within which to further refine legal positivist doctrine. The account should be of independent interest Dworkineans, and other non-positivists, as well, because it suggests that we cannot ultimately resolve these debates on the basis of facts about of legal authority

High Purity Electrolytic Manganese From Low-Grade Ore as a Substitute for Various Forms of Manganese Now being used in Metallurgical Industries

India produces about 1 million tons of high-grade manganese ores every year and about the same quantity of low-grade ores is being dumped in the mining areas. Besides high-grade ores she has abundant resources of low-grade ores for which there is practically no market. Investigations have already been undertaken in this country under the Five Year Plan to utilize these low-grade ores by different methods of beneficiation and also by the production of high purity electrolytic manganese. The purpose of this article is to discuss in the light of the experiments carried out in U.S.A. that high purity electrolytic manganese from low-grade ores can be substituted for different forms of manganese specially ferro-manganese now being employed in metallurgical industries. The main disadvantage in using electrolytic manganese is its comparatively high cost of production. A substantial reduction in the price can be expected if the demand for electrolytic manganese increases with increasing use. The present price of electrolytic manganese is 31 cents per pound. It has been estimated by the U.S. Bureau of Mines that in a 40 ton per day electrolytic manganese plant, the total operating cost, exclusive of taxes, interest, ore, sales and plant insurance, comes to about 7-2 cents per pound

Geometry of deformations of branes in warped backgrounds

The `braneworld' (described by the usual worldvolume action) is a D dimensional timelike surface embedded in a N dimensional ($N>D$) warped, nonfactorisable spacetime. We first address the conditions on the warp factor required to have an extremal flat brane in a five dimensional background. Subsequently, we deal with normal deformations of such extremal branes. The ensuing Jacobi equations are analysed to obtain the stability condition. It turns out that to have a stable brane, the warp factor should have a minimum at the location of the brane in the given background spacetime. To illustrate our results we explicitly check the extremality and stability criteria for a few known co-dimension one braneworld models. Generalisations of the above formalism for the cases of (i) curved branes (ii) asymmetrical warping and (iii) higher co-dimension braneworlds are then presented alongwith some typical examples for each. Finally, we summarize our results and provide perspectives for future work along these lines.Comment: 21 pages. Version matching final version. Accepted for publication in Class. Quant. Gra