Consistency in statistical moments as a test for bubble cloud clustering

Frequency dependent measurements of attenuation and/or sound speed through clouds of gas bubbles in liquids are often inverted to find the bubble size distribution and the void fraction of gas. The inversions are often done using an effective medium theory as a forward model under the assumption that the bubble positions are Poisson distributed (i.e., statistically independent). Under circumstances in which single scattering does not adequately describe the pressure field, the assumption of independence in position can yield large errors when clustering is present, leading to errors in the inverted bubble size distribution. It is difficult, however, to determine the existence of clustering in bubble clouds without the use of specialized acoustic or optical imaging equipment. A method is described here in which the existence of bubble clustering can be identified by examining the consistency between the first two statistical moments of multiple frequency acoustic measurements

An Estimate of the Gas Transfer Rate from Oceanic Bubbles Derived from Multibeam Sonar Observations of a Ship Wake

Measurements of gas transfer rates from bubbles have been made in the laboratory, but these are difficult to extrapolate to oceanic bubbles where populations of surfactants and particulate matter that inhibit gas transfer are different. Measurements at sea are complicated by unknown bubble creation rates that make it difficult to uniquely identify and observe the evolution of individual bubble clouds. One method that eliminates these difficulties is to measure bubbles in a ship wake where bubble creation at any given location is confined to the duration of the passing ship. This method assumes that the mechanisms slowing the gas dissolution of naturally created bubbles act in a similar manner to slow the dissolution of bubbles in a ship wake. A measurement of the gas transfer rate for oceanic bubbles using this method is reported here. A high-frequency upward-looking multibeam echosounder was used to measure the spatial distribution of bubbles in the wake of a twin screw 61-m research vessel. Hydrodynamic forcing functions are extracted from the multibeam data and used in a bubble cloud evolution model in which the gas transfer rate is treated as a free parameter. The output of model runs corresponding to different gas transfer rates is compared to the time-dependent wake depth observed in the data. Results indicating agreement between the model and the data show that the gas transfer rate must be approximately 15 times less then it would be for surfactant-free bubbles in order to explain the bubble persistence in the wake

Zombie Mortgages, Real Estate, and the Fallout for the Survivors

Part I of this Article will briefly explain the context and scope of the problem, how it typically arises, and how the problem was exacerbated by the larger real estate crisis in the latter half of the 2000s. Zombie properties are problematic for the affected homeowners, but in many cases they are equally problematic for other individuals residing in the same neighborhood, the lenders and servicers, and the relevant municipalities who will have to face issues of negligence, blight and vandalism related to vacant properties. Part I will analyze current municipal approaches to dealing with the problem, primarily through vacant property registration ordinances (VPROs). In the search for a solution to this crisis, both lenders and borrowers will likely need to share in the financial responsibility for these properties. Part II will examine cases from both municipal driven litigation as well as consumer-driven litigation where zombie debt has been legally extinguished. Part II will also examine several bankruptcy decisions that potentially lead to an avenue of relief for the owners of the affected properties. Part III proposes two new unique ordinances that cities could use to combat the problem, highlights owner-based solutions in bankruptcy, and mentions other attempts that have been tried in erasing zombie mortgages. This article concludes that a compromise solution that involves the municipalities, lenders and borrowers is the best route to ease the nationwide problems associated with zombie mortgages

(Unfair) Advantage: Damocles’ Sword and the Coercive Use of Immigration Status in a Civil Society

This article argues that the coercive use of immigration status or “status coercion” in civil proceedings and negotiations is fundamentally unethical and potentially illegal. For attorneys attempting to take advantage of unauthorized immigration status, such conduct very likely violates an attorney\u27s ethical obligations under the Rules of Professional Responsibility and wrongfully takes advantage of an overly vulnerable population. For the judiciary, the article argues for a more proactive approach in maintaining the perception of fairness and justice in civil proceedings for all parties, regardless of immigration status. Additionally, for both legal and lay persons, status coercion may constitute the crime of extortion, and this article establishes how status coercion in most cases fills the required elements of extortion. Part I of the article discusses in reported and unreported decisions the various fora where the described harms most often occur, including specifically commercial disputes, custody litigation and employment law issues where case outcomes have hinged on immigration status, and analyzes the impetus for the harms and the consequences, where appropriate, of the same. Part II of the article looks at ethical obligations, primarily those imposed by the Rules of Professional Responsibility on attorneys and the Model Code of Judicial Conduct for judges. Part II also looks in a more narrow perspective at potential criminal prohibitions and sanctions regulating this type of behavior affecting all parties. Part III suggests potential remedies available to the unauthorized immigrant in both civil and immigration proceedings when faced with status coercion. Part IV concludes that current ethical and legal obligations imposed on community members should be sufficient to prevent status coercion in commercial and civil contexts in the vast majority of cases. The article concludes that as unauthorized immigrants are one of the most vulnerable and susceptible populations to harm done to them, the ethical rules governing lawyers and judges should clearly state, and be understood, as prohibiting this type of coercion

High-throughput colorimetric method for the parallel assay of glyoxylic acid and ammonium in a single extract

Bräutigam A, Gagneul D, Weber APM. High-throughput colorimetric method for the parallel assay of glyoxylic acid and ammonium in a single extract. Analytical Biochemistry. 2007;362(1):151-153

Incorporating Uncertainties in Atomic Data Into the Analysis of Solar and Stellar Observations: A Case Study in Fe XIII

Information about the physical properties of astrophysical objects cannot be measured directly but is inferred by interpreting spectroscopic observations in the context of atomic physics calculations. Ratios of emission lines, for example, can be used to infer the electron density of the emitting plasma. Similarly, the relative intensities of emission lines formed over a wide range of temperatures yield information on the temperature structure. A critical component of this analysis is understanding how uncertainties in the underlying atomic physics propagates to the uncertainties in the inferred plasma parameters. At present, however, atomic physics databases do not include uncertainties on the atomic parameters and there is no established methodology for using them even if they did. In this paper we develop simple models for the uncertainties in the collision strengths and decay rates for Fe XIII and apply them to the interpretation of density sensitive lines observed with the EUV Imagining spectrometer (EIS) on Hinode. We incorporate these uncertainties in a Bayesian framework. We consider both a pragmatic Bayesian method where the atomic physics information is unaffected by the observed data, and a fully Bayesian method where the data can be used to probe the physics. The former generally increases the uncertainty in the inferred density by about a factor of 5 compared with models that incorporate only statistical uncertainties. The latter reduces the uncertainties on the inferred densities, but identifies areas of possible systematic problems with either the atomic physics or the observed intensities.Comment: in press at Ap

State And Local Regulation Of Immigration: The Need For A Bilateral (Reciprocal) Ratchet

The issue of federal preemption in the field of immigration has been swirling more and more strongly in academia, the courts, and even the public consciousness\u27 ever since De Canas v. Bica was decided in 1976