Algebraic Properties of BRST Coupled Doublets

We characterize the dependence on doublets of the cohomology of an arbitrary nilpotent differential s (including BRST differentials and classical linearized Slavnov-Taylor (ST) operators) in terms of the cohomology of the doublets-independent component of s. All cohomologies are computed in the space of local integrated formal power series. We drop the usual assumption that the counting operator for the doublets commutes with s (decoupled doublets) and discuss the general case where the counting operator does not commute with s (coupled doublets). The results are purely algebraic and do not rely on power-counting arguments.Comment: Some explanations enlarged, references adde

Background gauge invariance in the antifield formalism for theories with open gauge algebras

We show that any BRST invariant quantum action with open or closed gauge algebra has a corresponding local background gauge invariance. If the BRST symmetry is anomalous, but the anomaly can be removed in the antifield formalism, then the effective action possesses a local background gauge invariance. The presence of antifields (BRST sources) is necessary. As an example we analyze chiral $W_3$ gravity.Comment: 17pp., Latex, mispelling in my name! corrected, no other change

O clima da região de Dourados, MS.

O Clima da Região de Dourados, MS; Análise dos Principais Elementos Meteorológicos; Temperatura e umidade relativa do ar; Insolação e fotoperíodo; Vento; Evapotranspiração; Chuva; Veranicos e estiagens; Balanço hídrico; Ocorrência de Geadas; Classificação climática.bitstream/item/37989/1/DOC200892.pdf2. ed.1. ed. disponível apenas on-line

Avaliação de modelos de estimativa do saldo de radiação e do método de Priestley-Taylor para a região de Dourados, MS.

Agriambi

Power-law correlations and orientational glass in random-field Heisenberg models

Monte Carlo simulations have been used to study a discretized Heisenberg ferromagnet (FM) in a random field on simple cubic lattices. The spin variable on each site is chosen from the twelve [110] directions. The random field has infinite strength and a random direction on a fraction x of the sites of the lattice, and is zero on the remaining sites. For x = 0 there are two phase transitions. At low temperatures there is a [110] FM phase, and at intermediate temperature there is a [111] FM phase. For x > 0 there is an intermediate phase between the paramagnet and the ferromagnet, which is characterized by a |k|^(-3) decay of two-spin correlations, but no true FM order. The [111] FM phase becomes unstable at a small value of x. At x = 1/8 the [110] FM phase has disappeared, but the power-law correlated phase survives.Comment: 8 pages, 12 Postscript figure

Attorneys as Arbitrators

We study the role of attorneys as arbitrators in securities arbitration conducted by the National Association of Securities Dealers (NASD, n/k/a FINRA), using a dataset of 422 randomly selected arbitrators and their 6724 arbitration awards from 1992 to 2006. We find that arbitrators who also represent brokerage firms or brokers in other arbitrations award significantly less compensation to investor-claimants than other arbitrators. We find no significant effect for attorney-arbitrators who represent investors or both investors and brokerage firms. The relation between representing brokerage firms and arbitration awards remains significant even when we control for political outlook. We report that ideology correlates significantly with arbitration awards – arbitrators who donate money to Democratic political candidates award greater compensation than arbitrators who donate to Republican candidates. Because the arbitration award is the product of the panel, not a single arbitrator, we also study the dynamics of panel interaction. We find that the position of chair is an important factor in assessing the arbitrator’s influence, although the financial relationships of other arbitrators may also affect arbitration awards. Coalitions with the other arbitrators are also important. If the chair and another panelist possess a common attribute, the effect on the arbitration award increases. Finally, we provide evidence that the 1998 reforms to the arbitration process – which introduced party control over the composition of panels – ameliorated, but did not eliminate, the effect that attorneys who represent brokers have on outcomes. We find no significant effect from the NASD’s 2004 reforms

Subextensive singularity in the 2D ±J\pm J Ising spin glass

The statistics of low energy states of the 2D Ising spin glass with +1 and -1 bonds are studied for $L \times L$ square lattices with $L \le 48$, and $p$ = 0.5, where $p$ is the fraction of negative bonds, using periodic and/or antiperiodic boundary conditions. The behavior of the density of states near the ground state energy is analyzed as a function of $L$, in order to obtain the low temperature behavior of the model. For large finite $L$ there is a range of $T$ in which the heat capacity is proportional to $T^{5.33 \pm 0.12}$. The range of $T$ in which this behavior occurs scales slowly to $T = 0$ as $L$ increases. Similar results are found for $p$ = 0.25. Our results indicate that this model probably obeys the ordinary hyperscaling relation $d \nu = 2 - \alpha$, even though $T_c = 0$. The existence of the subextensive behavior is attributed to long-range correlations between zero-energy domain walls, and evidence of such correlations is presented.Comment: 13 pages, 7 figures; final version, to appear in J. Stat. Phy

Development of high temperature oxidation resistant coatings for chromium-base alloys Final report

High temperature oxidation resistant coatings for chromium-base alloy

Do Institutions Matter? The Impact of the Lead Plaintiff Provision of the Private Securities Litigation Reform Act

When Congress enacted the Private Securities Litigation Reform Act in 1995 (“PSLRA”), the Act’s “lead plaintiff” provision was the centerpiece of its efforts to increase investor control over securities fraud class actions. The lead plaintiff provision alters the balance of power between investors and class counsel by creating a presumption that the investor with the largest financial stake in the case will serve as lead plaintiff. The lead plaintiff then chooses class counsel and, at least in theory, negotiates the terms of counsel’s compensation. Congress’s stated purpose in enacting the lead plaintiff provision was to encourage institutional investors—pension funds, mutual funds, hedge funds, etc.—to come forward to serve as lead plaintiff. The theory was that an institutional investor with a substantial damages claim would have the incentive to bargain hard with class counsel on behalf of the class, reducing the percentage of the recovery awarded to class counsel. Congress also expected institutions to play an oversight role, monitoring to make sure that class counsel was vigorously pursuing claims on behalf of the class and not settling claims on the cheap. Our study offers evidence on the extent to which the lead plaintiff provision furthers these goals. We have collected two samples of securities class actions—one from 1991 to 1995 (pre-PSLRA) and one from 1996 to 2000 (post-PSLRA). We compare the class representatives from the two periods to determine if institutional investors are stepping forward in significantly greater numbers. We also sort the institutional investors—distinguishing public from private—to see what types of investors have stepped forward to serve as lead plaintiff. Consistent with other research, we find a significant difference only in the number of public institutions serving as lead plaintiff. Our sample also allows us to analyze the impact of the lead plaintiff provision: Does the presence of an institutional investor increase the likelihood of a high-value settlement? Despite the visible participation of institutions in several high-profile cases, we find no systematic evidence that private institutional lead plaintiffs are associated with larger class recoveries. Public pension fund lead plaintiffs, on the other hand, are correlated with higher class recoveries as a fraction of the potential damage award in the post-PSLRA period. Our results are, however, consistent with the possibility that public pensions “cherry-pick” the actions in which they seek to become lead plaintiff, selecting only the cases with the largest potential damages and the strongest evidence of fraud. Further analysis is needed to evaluate this possibility. We also evaluate the effect of lead plaintiffs on the selection of attorneys and attorneys’ fees. We find that, for the time period of our study, institutional investors tended to avoid the Milberg Weiss plaintiffs’ attorney firm. On the more fundamental issue of whether the presence of an institutional investor as a lead plaintiff reduces the fees paid to the lawyers, after controlling for the size of the case, we find no systematic evidence that institutional involvement correlates with lower fee awards