558 research outputs found
A Policy Analysis of Fee-Shifting Rules Under the Internal Revenue Code
Until recently, the costs of litigating federal tax cases were borne exclusively by the parties who incurred them, regardless of whether the government or the taxpayer prevailed in the litigation. This practice reflects the application to tax disputes of the ‘American rule’ against fee shifting. Although the American rule continues to be predominant in the tax area, it has been modified in important respects. An explicit fee-reimbursement rule, benefiting prevailing taxpayers in cases in which the government is found to have acted unreasonably, was added to the Internal Revenue Code (IRC) by the Tax Equity and Fiscal Responsibility Act of 1982 (TEFRA). TEFRA also increased substantially the penalties that could be imposed on taxpayers who are found to have instituted tax litigation on frivolous grounds, or primarily for delay. The provisions are not precise counterparts of each other: one is a true fee-reimbursement rule, while the other is a penalty provision that is not directly tied to litigation costs. Nevertheless, the rules are similar in their effects on incentives to litigate tax cases. This article begins with a brief description and history of these provisions, followed by an analysis of their impact on litigation decisionmaking in the tax area. We argue that the present mix of fee-shifting rules in tax cases represents an attractive hybrid of the American rule and the ‘English rule,’ which normally allows recovery of costs by the prevailing party. The hybrid rule seems likely to deter parties from bringing poorly grounded cases to court without discouraging litigants with sounder positions. It thus combines the best features of each of the more traditional rules. After analyzing the hybrid rule, we discuss the recent changes to the rule made by the Tax Reform Act of 1986 and argue that those changes, on balance, do not represent improvements over the original TEFRA rules, and may indeed prove troublesome in the coming years
The Value of Singularities
We point out that spacetime singularities play a useful role in gravitational
theories by eliminating unphysical solutions. In particular, we argue that any
modification of general relativity which is completely nonsingular cannot have
a stable ground state. This argument applies both to classical extensions of
general relativity, and to candidate quantum theories of gravity.Comment: 5 pages, no figures; a few clarifying comments adde
Black Holes Radiate Mainly on the Brane
We examine the evaporation of a small black hole on a brane in a world with
large extra dimensions. Since the masses of many Kaluza-Klein modes are much
smaller than the Hawking temperature of the black hole, it has been claimed
that most of the energy is radiated into these modes. We show that this is
incorrect. Most of the energy goes into the modes on the brane. This raises the
possibility of observing Hawking radiation in future high energy colliders if
there are large extra dimensions.Comment: 11 page
Protein Complexes are Central in the Yeast Genetic Landscape
If perturbing two genes together has a stronger or weaker effect than expected, they are said to genetically interact. Genetic interactions are important because they help map gene function, and functionally related genes have similar genetic interaction patterns. Mapping quantitative (positive and negative) genetic interactions on a global scale has recently become possible. This data clearly shows groups of genes connected by predominantly positive or negative interactions, termed monochromatic groups. These groups often correspond to functional modules, like biological processes or complexes, or connections between modules. However it is not yet known how these patterns globally relate to known functional modules. Here we systematically study the monochromatic nature of known biological processes using the largest quantitative genetic interaction data set available, which includes fitness measurements for ∼5.4 million gene pairs in the yeast Saccharomyces cerevisiae. We find that only 10% of biological processes, as defined by Gene Ontology annotations, and less than 1% of inter-process connections are monochromatic. Further, we show that protein complexes are responsible for a surprisingly large fraction of these patterns. This suggests that complexes play a central role in shaping the monochromatic landscape of biological processes. Altogether this work shows that both positive and negative monochromatic patterns are found in known biological processes and in their connections and that protein complexes play an important role in these patterns. The monochromatic processes, complexes and connections we find chart a hierarchical and modular map of sensitive and redundant biological systems in the yeast cell that will be useful for gene function prediction and comparison across phenotypes and organisms. Furthermore the analysis methods we develop are applicable to other species for which genetic interactions will progressively become more available
The Decay of Magnetic Fields in Kaluza-Klein Theory
Magnetic fields in five-dimensional Kaluza-Klein theory compactified on a
circle correspond to ``twisted'' identifications of five dimensional Minkowski
space. We show that a five dimensional generalisation of the Kerr solution can
be analytically continued to construct an instanton that gives rise to two
possible decay modes of a magnetic field. One decay mode is the generalisation
of the ``bubble decay" of the Kaluza-Klein vacuum described by Witten. The
other decay mode, rarer for weak fields, corresponds in four dimensions to the
creation of monopole-anti-monopole pairs. An instanton for the latter process
is already known and is given by the analytic continuation of the \KK\ Ernst
metric, which we show is identical to the five dimensional Kerr solution. We
use this fact to illuminate further properties of the decay process. It appears
that fundamental fermions can eliminate the bubble decay of the magnetic field,
while allowing the pair production of Kaluza-Klein monopoles.Comment: 25 pages, one figure. The discussion of fermions has been revised: We
show how fundamental fermions can eliminate the bubble-type instability but
still allow pair creation of monopole
Bringing order to protein disorder through comparative genomics and genetic interactions
Abstract
Background
Intrinsically disordered regions are widespread, especially in proteomes of higher eukaryotes. Recently, protein disorder has been associated with a wide variety of cellular processes and has been implicated in several human diseases. Despite its apparent functional importance, the sheer range of different roles played by protein disorder often makes its exact contribution difficult to interpret.
Results
We attempt to better understand the different roles of disorder using a novel analysis that leverages both comparative genomics and genetic interactions. Strikingly, we find that disorder can be partitioned into three biologically distinct phenomena: regions where disorder is conserved but with quickly evolving amino acid sequences (flexible disorder); regions of conserved disorder with also highly conserved amino acid sequences (constrained disorder); and, lastly, non-conserved disorder. Flexible disorder bears many of the characteristics commonly attributed to disorder and is associated with signaling pathways and multi-functionality. Conversely, constrained disorder has markedly different functional attributes and is involved in RNA binding and protein chaperones. Finally, non-conserved disorder lacks clear functional hallmarks based on our analysis.
Conclusions
Our new perspective on protein disorder clarifies a variety of previous results by putting them into a systematic framework. Moreover, the clear and distinct functional association of flexible and constrained disorder will allow for new approaches and more specific algorithms for disorder detection in a functional context. Finally, in flexible disordered regions, we demonstrate clear evolutionary selection of protein disorder with little selection on primary structure, which has important implications for sequence-based studies of protein structure and evolution
Uniqueness and non-uniqueness of static vacuum black holes in higher dimensions
We prove the uniqueness theorem for asymptotically flat static vacuum black
hole solutions in higher dimensional space-times. We also construct infinitely
many non-asymptotically flat regular static black holes on the same spacetime
manifold with the same spherical topology.Comment: to appear in Progress of Theoretical Physics Supplement No. 14
On the Nonlinear Stability of Asymptotically Anti-de Sitter Solutions
Despite the recent evidence that anti-de Sitter spacetime is nonlinearly
unstable, we argue that many asymptotically anti-de Sitter solutions are
nonlinearly stable. This includes geons, boson stars, and black holes. As part
of our argument, we calculate the frequencies of long-lived gravitational
quasinormal modes of AdS black holes in various dimensions. We also discuss a
new class of asymptotically anti-de Sitter solutions describing noncoalescing
black hole binaries.Comment: 26 pages. 5 figure
The Extreme Kerr Throat Geometry: A Vacuum Analog of AdS_2 x S^2
We study the near horizon limit of a four dimensional extreme rotating black
hole. The limiting metric is a completely nonsingular vacuum solution, with an
enhanced symmetry group SL(2,R) x U(1). We show that many of the properties of
this solution are similar to the AdS_2 x S^2 geometry arising in the near
horizon limit of extreme charged black holes. In particular, the boundary at
infinity is a timelike surface. This suggests the possibility of a dual quantum
mechanical description. A five dimensional generalization is also discussed.Comment: 21 page
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