The Failed Critique of Personal Accounts

Even though President Bush's Commission to Strengthen Social Security has yet to produce a specific proposal to establish a personal account option for Social Security, opponents of the idea have already put forward a barrage of objections and criticisms. Those criticisms generally reflect fundamental misconceptions of and confusion about Social Security's current problems. Social Security is facing a financial crisis as early as 2016. The Social Security Trust Fund will not delay the onset of Social Security's problems. The critics are equally mistaken about individual accounts. Individual accounts do not involve simply switching investments from bonds to stocks. There would be no reduction in survivors' or disability benefits. Although the mix of benefits would change, workers would have higher, not lower, overall benefits under individual accounts. Finally, benefits under the current system are not guaranteed, but workers would have a property right to the funds in their individual accounts

10 Reasons to Oppose Virginia Sales Tax Increases

Northern and southeastern Virginians will vote in referenda this November to approve or reject increases in the retail sales tax to fund transportation projects. Northern Virginians will decide whether to increase the sales tax from 4.5 percent to 5.0 percent, an 11 percent increase. Virginians in the Hampton Roads area will decide whether to increase the sales tax from 4.5 percent to 5.5 percent, a 22 percent increase. Proponents of tax increases point to unmet transportation needs to support their cause. Yet state spending increased 13 percent in 1999, 7 percent in 2000, and 9 percent in 2001. If key transportation needs have not been met, the problem is not a lack of funds but legislators who have not properly prioritized the budget. If the sales tax referenda are passed, the state government will have a strong incentive to reduce what it would otherwise spend on transportation in northern Virginia and Hampton Roads. By some measures, northern Virginia already gets the short end of the stick with regard to the state budget. Tax increases are not just bad budget policy; they are also bad economic policy. Since higher taxes reduce economic growth, an added cost of higher sales taxes would be lower incomes for Virginians. During the 1990s Virginia taxes grew faster than incomes, and local property taxes have soared recently. Even modest restraint in nontransportation spending could save enough money to fund priority highway projects without tax increases. Further, the state could adopt a spending growth cap that channels excess future tax revenues to transportation needs and tax cuts

Quadratic Divergences in Kaluza-Klein Theories

We investigate the so-called ``Kaluza-Klein regularisation'' procedure in supersymmetric extensions of the standard model with additional compact dimensions and Scherk-Schwarz mechanism for supersymmetry breaking. This procedure uses a specific mathematical manipulation to obtain a finite result for the scalar potential. By performing the full calculation, we show that the finiteness of this result is not only a consequence of the underlying supersymmetry, but also the result of an implicit fine-tuning of the coefficients of the terms that control the ultraviolet behaviour. The finiteness of the Higgs mass at one-loop level seems therefore to be an artefact of the regularisation scheme, and quadratic divergences are expected to reappear in higher orders of perturbation theory.Comment: 10 pages, LaTe

Peripheral nerve-derived VEGF promotes arterial differentiation via neuropilin 1-mediated positive feedback

In developing limb skin, peripheral nerves are required for arterial differentiation, and guide the pattern of arterial branching. In vitro experiments suggest that nerve-derived VEGF may be important for arteriogenesis, but its role in vivo remains unclear. Using a series of nerve-specific Cre lines, we show that VEGF derived from sensory neurons, motoneurons and/or Schwann cells is required for arteriogenesis in vivo. Arteriogenesis also requires endothelial expression of NRP1, an artery-specific coreceptor for VEGF^(164) that is itself induced by VEGF. Our results provide the first evidence that VEGF is necessary for arteriogenesis from a primitive capillary plexus in vivo, and show that in limb skin the nerve is indeed the principal source of this signal. They also suggest a model in which a `winner-takes-all' competition for VEGF may control arterial differentiation, with the outcome biased by a VEGF^(164)-NRP1 positive-feedback loop. Our results also demonstrate that nerve-vessel alignment is a necessary, but not sufficient, condition for nerve-induced arteriogenesis. Different mechanisms therefore probably underlie these endothelial patterning and differentiation processes

Non-Perturbative Green's Functions in Theories with Extended Superconformal Symmetry

The multiplets that occur in four dimensional rigidly supersymmetric theories can be described either by chiral superfields in Minkowski superspace or analytic superfields in harmonic superspace. The superconformal Ward identities for Green's functions of gauge invariant operators of these types are derived. It is shown that there are no chiral superconformal invariants. It is further shown that the Green's functions of analytic operators are severely restricted by the superconformal Ward when analyticity is taken into account.Comment: 17 pages, plain tex. Some conjectures that were in the original paper are clarifed in the light of more recent work to which we give references. See Note added for detail

Threshold Corrections to Gauge Couplings in Orbifold Compactifications

We derive the moduli dependent threshold corrections to gauge couplings in toroidal orbifold compactifications. The underlying six dimensional torus lattice of the heterotic string theory is not assumed ---as in previous calculations--- to decompose into a direct sum of a four--dimensional and a two--dimensional sublattice, with the latter lying in a plane left fixed by a set of orbifold twists. In this more general case the threshold corrections are no longer automorphic functions of the modular group, but of certain congruence subgroups of the modular group. These groups can also be obtained by studying the massless spectrum; moreover they have larger classes of automorphic functions. As a consequence the threshold corrections cannot be uniquely determined by symmetry considerations and certain boundary conditions at special points in the moduli space, as was claimed in previous publications.Comment: 20 pages (Latex) (There was a minor Latex error in the original version. This is removed now