Ultrastructural alteration of mouse lung by prolonged exposure to mixtures of helium and oxygen

Observed changes consist mainly of blebbing of capillary endothelium and alveolar epithelium, which is quite possibly indicative of cellular edema; also, there can be observed highly-convoluted basement membrane, alveolar debris, and increased numbers of platelets

A new look at the problem of gauge invariance in quantum field theory

Quantum field theory is assumed to be gauge invariant. However it is well known that when certain quantities are calculated using perturbation theory the results are not gauge invariant. The non-gauge invariant terms have to be removed in order to obtain a physically correct result. In this paper we will examine this problem and determine why a theory that is supposed to be gauge invariant produces non-gauge invariant results.Comment: Accepted by Physica Scripta. 27 page

Confronting the Peppercorn Settlement in Merger Litigation: An Empirical Analysis and a Proposal for Reform

Shareholder litigation challenging corporate mergers is ubiquitous, with the likelihood of a shareholder suit exceeding 90%. The value of this litigation, however, is questionable. The vast majority of merger cases settle for nothing more than supplemental disclosures in the merger proxy statement. The attorneys that bring these lawsuits are compensated for their efforts with a court-awarded fee. This leads critics to charge that merger litigation benefits only the lawyers who bring the claims, not the shareholders they represent. In response, defenders of merger litigation argue that the lawsuits serve a useful oversight function and that the improved disclosures that result are beneficial to shareholders. This Article offers a new approach to assessing the value of these claims by empirically testing the relationship between merger litigation and shareholder voting on the merger. If the supplemental disclosures produced by the settlement of merger litigation are valuable, they should affect shareholder voting behavior. Specifically, supplemental disclosures that are, in effect, “compelled” by settlement should produce new and unfavorable information about the merger and lead to a lower percentage of shares voted in favor of it. Applying this hypothesis to a hand-collected sample of 453 large public company mergers from 2005-2012, we find no such effect. We find no significant evidence that disclosure-only settlements affect shareholder voting. These findings warrant a reconsideration of Delaware merger law. Specifically, under current law, supplemental disclosures are viewed by courts as providing a substantial benefit to the shareholder class. In turn, this substantial benefit entitles the plaintiffs’ lawyers to an award of attorneys’ fees. Our evidence suggests that this legal analysis is misguided and that supplemental disclosures do not in fact constitute a substantial benefit. As a result, and in light of the substantial costs generated by public company merger litigation, we argue that courts should reject disclosure settlements as a basis for attorney fee awards. Our approach responds to critiques of merger litigation as excessive and frivolous by reducing the incentive for plaintiffs’ lawyers to bring weak cases, but it would have an additional benefit. Current practice drags state court judges into the task of indirectly promulgating disclosure standards in connection with the approval of fee awards. We argue, instead, for a more efficient specialization between state and federal courts in the regulation of mergers: public company merger disclosure should be policed by the federal securities laws while state corporate law focuses on substantive fairness

Confronting the Peppercorn Settlement in Merger Litigation: An Empirical Analysis and a Proposal for Reform

Shareholder litigation challenging corporate mergers is ubiquitous, with the likelihood of a shareholder suit exceeding 90%. The value of this litigation, however, is questionable. The vast majority of merger cases settle for nothing more than supplemental disclosures in the merger proxy statement. The attorneys that bring these lawsuits are compensated for their efforts with a court-awarded fee. This leads critics to charge that merger litigation benefits only the lawyers who bring the claims, not the shareholders they represent. In response, defenders of merger litigation argue that the lawsuits serve a useful oversight function and that the improved disclosures that result are beneficial to shareholders. This Article offers a new approach to assessing the value of these claims by empirically testing the relationship between merger litigation and shareholder voting on the merger. If the supplemental disclosures produced by the settlement of merger litigation are valuable, they should affect shareholder voting behavior. Specifically, supplemental disclosures that are, in effect, “compelled” by settlement should produce new and unfavorable information about the merger and lead to a lower percentage of shares voted in favor of it. Applying this hypothesis to a hand-collected sample of 453 large public company mergers from 2005-2012, we find no such effect. We find no significant evidence that disclosure-only settlements affect shareholder voting. These findings warrant a reconsideration of Delaware merger law. Specifically, under current law, supplemental disclosures are viewed by courts as providing a substantial benefit to the shareholder class. In turn, this substantial benefit entitles the plaintiffs’ lawyers to an award of attorneys’ fees. Our evidence suggests that this legal analysis is misguided and that supplemental disclosures do not in fact constitute a substantial benefit. As a result, and in light of the substantial costs generated by public company merger litigation, we argue that courts should reject disclosure settlements as a basis for attorney fee awards. Our approach responds to critiques of merger litigation as excessive and frivolous by reducing the incentive for plaintiffs’ lawyers to bring weak cases, but it would have an additional benefit. Current practice drags state court judges into the task of indirectly promulgating disclosure standards in connection with the approval of fee awards. We argue, instead, for a more efficient specialization between state and federal courts in the regulation of mergers: public company merger disclosure should be policed by the federal securities laws while state corporate law focuses on substantive fairness

The essential signature of a massive starburst in a distant galaxy

Observations of carbon monoxide (CO) emission in high redshift (z>2) galaxies indicate the presence of large amounts of molecular gas. Many of these galaxies contain an active galactic nucleus (AGN) powered by accretion of gas onto a supermassive black hole, and a key question is whether their extremely high infrared luminosities result from the AGN, or from bursts of massive star formation (associated with the molecular gas), or both. In the Milky Way, high-mass stars form in the dense cores of interstellar molecular clouds; gas densities are n(H2)>105 cm-3 in the cores. Recent surveys show that virtually all galactic sites of high-mass star formation have similarly high densities. The bulk of the cloud material traced by CO observations is at a much lower density. In galaxies in the local Universe, the HCN(J=1-0) line is an effective tracer of the high-density molecular gas. Here we report observations of HCN emission in the early Universe from the infrared luminous 'Cloverleaf' quasar (at a redshift z=2.5579). The HCN line luminosity indicates the presence of 10 billion solar masses of very dense gas, an essential feature of an immense starburst that contributes, together with the AGN it harbors, to its high infrared luminosity.Comment: PDF pape

STOCHASTIC WEALTH DYNAMICS AND RISK MANAGEMENT AMONG A POOR POPULATION

The literature on economic growth and development has focused considerable attention on questions of risk management and the possibility of multiple equilibria associated with poverty traps. We use herd history data collected among pastoralists in southern Ethiopia to study stochastic wealth dynamics among a very poor population. These data yield several novel findings. Although covariate rainfall shocks plainly matter, household-specific factors, including own herd size, account for most observed variability in wealth dynamics. Despite longstanding conventional wisdom about common property grazing lands, we find no statistical support for the tragedy of the commons hypothesis. It appears that past studies may have conflated costly self-insurance with stocking rate externalities. Such self-insurance is important in this setting because weak livestock markets and meager social insurance cause wealth to fluctuate largely in response to biophysical shocks. These shocks move households between multiple dynamic wealth equilibria toward which households converge following nonconvex path dynamics. The lowest equilibrium is consistent with the notion of a poverty trap. These findings have broad implications for the design of development and relief strategies among a poor population extraordinarily vulnerable to climatic shocks.common property, covariate risk, Ethiopia, idiosyncratic risk, poverty traps, social insurance, Risk and Uncertainty, O1, Q12,

Dense Molecular Gas and the Role of Star Formation in the Host Galaxies of Quasi-Stellar Objects

New millimeter-wave CO and HCN observations of the host galaxies of infrared-excess Palomar Green quasi-stellar objects (PG QSOs) previously detected in CO are presented. These observations are designed to assess the validity of using the infrared luminosity to estimate star formation rates of luminous AGN by determining the relative significance of dust-heating by young, massive stars and active galactic nuclei (AGN) in QSO hosts and IRAS galaxies with warm, AGN-like infrared colors. The HCN data show the PG QSO host IZw1 and most of the warm IRAS galaxies to have high L_IR / L'_HCN (>1600) relative to the cool IRAS galaxy population for which the median L_IR / L'_HCN ~ 890(+440,-470). If the assumption is made that the infrared emission from cool IRAS galaxies is reprocessed light from embedded star-forming regions, then high values of L_IR / L'_HCN are likely the result of dust heating by the AGN. Further, if the median ratio of L'_HCN / L'_CO ~ 0.06 observed for Seyfert galaxies and IZw1 is applied to the PG QSOs not detected in HCN, then the derived L_IR / L'_HCN correspond to a stellar contribution to the production of L_IR of ~ 7-39%, and star formation rates ~ 2-37 M_sun/yr are derived for the QSO hosts. Alternatively, if the far-infrared is adopted as the star formation component of the total infrared in cool galaxies, the stellar contributions in QSO hosts to their L_FIR are up to 35% higher than the percentages derived for L_IR. This raises the possibility that the L_FIR in several of the PG QSO hosts, including IZw1, could be due entirely to dust heated by young, massive stars. Finally, there is no evidence that the global HCN emission is enhanced relative to CO in galaxies hosting luminous AGN.Comment: LaTex, 31 pages, including 9 postscript figures, AJ, in press (December 2006

Trilogy on Computing Maximal Eigenpair

The eigenpair here means the twins consist of eigenvalue and its eigenvector. This paper introduces the three steps of our study on computing the maximal eigenpair. In the first two steps, we construct efficient initials for a known but dangerous algorithm, first for tridiagonal matrices and then for irreducible matrices, having nonnegative off-diagonal elements. In the third step, we present two global algorithms which are still efficient and work well for a quite large class of matrices, even complex for instance.Comment: Updated versio

Acute military psychiatric casualties from the war in Iraq

Background: The view that most military personnel evacuated from war zones are suffering from combat stress reactions, or are otherwise traumatised by the horrors of war, has an impact on all aspects of military psychiatry. Aims: To delineate the reasons for psychiatric aeromedical evacuation from Iraq from the start of build-up of UK forces in January 2003 until the end of October that year, 6 months after the end of formal hostilities. Method: A retrospective study was conducted of field and in-patient psychiatric assessments of 116 military personnel evacuated to the UK military psychiatric in-patient facility in Catterick Garrison. Results: Evacuees were mainly non-combatants (69%). A significant proportion were in reserve service (21%) and had a history of contact with mental health services (37%). Only 3% had a combat stress reaction. In over 85% of cases evacuation was for low mood attributed to separation from friends or family, or difficulties adjusting to the environment. Conclusions: These findings have implications especially for screening for suitability for deployment, and for understanding any longer-term mental health problems arising in veterans from Iraq

The Molecular Interstellar Medium in Ultraluminous Infrared Galaxies

We present CO observations of a large sample of ultraluminous IR galaxies out to z = 0.3. Most of the galaxies are interacting, but not completed mergers. All but one have high CO(1-0) luminosities, log(Lco [K-km/s-pc^2]) = 9.92 +/- 0.12. The dispersion in Lco is only 30%, less than that in the FIR luminosity. The integrated CO intensity correlates Strongly with the 100 micron flux density, as expected for a black body model in which the mid and far IR radiation are optically thick. We use this model to derive sizes of the FIR and CO emitting regions and the enclosed dynamical masses. Both the IR and CO emission originate in regions a few hundred parsecs in radius. The median value of Lfir/Lco = 160 Lsun/(K-km/s-pc^2), within a factor of two of the black body limit for the observed FIR temperatures. The entire ISM is a scaled up version of a normal galactic disk with densities a factor of 100 higher, making even the intercloud medium a molecular region. Using three different techniques of H2 mass estimation, we conclude that the ratio of gas mass to Lco is about a factor of four lower than for Galactic molecular clouds, but that the gas mass is a large fraction of the dynamical mass. Our analysis of CO emission reduces the H2 mass from previous estimates of 2-5e10 Msun to 0.4-1.5e10 Msun, which is in the range found for molecular gas rich spiral galaxies. A collision involving a molecular gas rich spiral could lead to an ultraluminous galaxy powered by central starbursts triggered by the compression of infalling preexisting GMC's.Comment: 34 pages LaTeX with aasms.sty, 14 Postscript figures, submitted to ApJ Higher quality versions of Figs 2a-f and 7a-c available by anonymous FTP from ftp://sbast1.ess.sunysb.edu/solomon/