LISA Source Confusion

The Laser Interferometer Space Antenna (LISA) will detect thousands of gravitational wave sources. Many of these sources will be overlapping in the sense that their signals will have a non-zero cross-correlation. Such overlaps lead to source confusion, which adversely affects how well we can extract information about the individual sources. Here we study how source confusion impacts parameter estimation for galactic compact binaries, with emphasis on the effects of the number of overlaping sources, the time of observation, the gravitational wave frequencies of the sources, and the degree of the signal correlations. Our main findings are that the parameter resolution decays exponentially with the number of overlapping sources, and super-exponentially with the degree of cross-correlation. We also find that an extended mission lifetime is key to disentangling the source confusion as the parameter resolution for overlapping sources improves much faster than the usual square root of the observation time.Comment: 8 pages, 14 figure

The Silver Anniversary of the United States’ Exclusive Economic Zone: Twenty-Five Years of Ocean Use and Abuse, and the Possibility of a Blue Water Public Trust Doctrine

Sustainably managing marine ecosystems has proved nearly impossible, with few success stories. Ecosystem management failures largely stem from the traditional sector-by-sector, issue-by-issue approach to managing ocean-borne activities—an approach that is fundamentally unable to keep pace with the dynamics of coupled human, ecologi cal and oceanographic systems. In the United States today there are over twenty federal agencies and thirty-five coastal states and territories operating under dozens of statutory authorities shaping coastal and ocean policy. Among marine ecologists and policy experts there is an emerging consensus that a major overhaul in U.S. ocean governance is necessary. This Article suggests that the public trust doctrine—an ancient legal concept that is already incorporated in U.S. state coastal laws—can uniquely provide a unifying concept for U.S. federal ocean governance. Though the public trust concept can be located in the legal systems of many countries, it robustly manifests in the United States, where it has historically protected the public’s rights to fishing, navigation, and commerce in and over navigable waterways and tidal waters. In its most basic form, the doctrine obliges governments to manage common natural resources, the body of the trust, in the best interest of their citizens, the beneficiaries of the trust. Today the public trust doctrin e is integral to the protection of coastal ecosystems and beach access in many states and has even made its way into state constitutions. It would be simple, and seemingly logical, to assume that the same fiduciary responsibility of states to protect public trust uses of their waters extends to all marine resources within the United States’ 200-mile Exclusive Economic Zone (EEZ). However an artificial line has been drawn around state waters, and the legal authority and responsibility of the U.S. government to protect public trust resources in the vast space of its EEZ (the largest of any country on earth) have never been fully and expressly established. Securing the place of the public trust doctrine in U.S. federal oceans management would be valuable, given the immense pressure to exploit EEZ resources, the failure of the current regulatory approach, improved scientific understanding of the interconnected nature of ocean ecosystems, and the growing demand for sustainable management of ocean resources. This Article will outline the development of states’ public trust doctrines; discuss the expansion of U.S. sovereignty over its neighboring ocean waters during the twentieth century; analyze possible avenues for expanding the doctrine to federal waters; and consider how a federal public trust doctrine could clarify some specific emerging issues in U.S. oceans management. At the heart of our analysis lie three questions: (1) does a federal public trust doctrine exist; (2) if so, can we rightfully extend it to include the entirety of the U.S. ocean waters; and (3) could the doctrine provide the missing catalyst for federal agencies to manage the use of U.S. ocean resources in a coordinated, sustainable fashion

Texas v. Cobb, The United States Supreme Court Limits the Sixth Amendment to Exonerate Innocent Suspects-Police Officers Acting in Good Faith

This Note argues that the Texas Court should adopt the Supreme Court\u27s holding in Cobb on state constitutional claims as well, thus avoiding further entanglement in the closely related confusion. For background purposes, Part II reviews the history of the Sixth Amendment right to counsel as provided by the Supreme Court and other lower courts prior to the Supreme Court\u27s decision in Cobb. Part III discusses Cobb\u27s facts and procedural history and examines the analyses of both the Texas Court and the Supreme Court. Part IV analyzes how the questions left unanswered by the Supreme Court, prior to Cobb, resulted in the Texas Court\u27s expansion of Sixth Amendment protections. Additionally, Part IV discusses why the Texas Court should recognize a defendant\u27s ability to waive his right to counsel after it has attached-an issue which was not addressed by the Supreme Court in Cobb. Part V discusses alternative grounds not considered by the Texas Court that could have also rendered Cobb\u27s confession admissible. In conclusion, this Note suggests how to resolve future Sixth Amendment questions in Texas

Integrating case-based reasoning and hypermedia documentation: an application for the diagnosis of a welding robot at Odense steel shipyard

Reliable and effective maintenance support is a vital consideration for the management within today's manufacturing environment. This paper discusses the development of a maintenance system for the world's largest robot welding facility. The development system combines a case-based reasoning approach for diagnosis with context information, as electronic on-line manuals, linked using open hypermedia technology. The work discussed in this paper delivers not only a maintenance system for the robot stations under consideration, but also a design framework for developing maintenance systems for other similar applications

Why Local Party Leaders Don't Support Nominating Centrists

Would giving party leaders more influence in primary elections in the United States decrease elite polarization? Some scholars have argued that political party leaders tend to support centrist candidates in the hopes of winning general elections. In contrast, the authors argue that many local party leaders - especially Republicans - may not believe that centrists perform better in elections and therefore may not support nominating them. They test this argument using data from an original survey of 1,118 county-level party leaders. In experiments, they find that local party leaders most prefer nominating candidates who are similar to typical co-partisans, not centrists. Moreover, given the choice between a more centrist and more extreme candidate, they strongly prefer extremists: Democrats do so by about 2 to 1 and Republicans by 10 to 1. Likewise, in open-ended questions, Democratic Party leaders are twice as likely to say they look for extreme candidates relative to centrists; Republican Party leaders are five times as likely. Potentially driving these partisan differences, Republican leaders are especially likely to believe that extremists can win general elections and overestimate the electorate's conservatism by double digits

Probing the Reaction Mechanism of the D-ala-D-ala Dipeptidase, VanX, by Using Stopped-Flow Kinetic and Rapid-Freeze Quench EPR Studies on the Co(II)-Substituted Enzyme

In an effort to probe the reaction mechanism of VanX, the D-ala-D-ala dipeptidase required for high-level vancomycin resistance in bacteria, stopped-flow kinetic and rapid-freeze quench EPR studies were conducted on the Co(II)-substituted enzyme when reacted with d-ala-d-ala. The intensity of the Co(II) ligand field band at 550 nm decreased (ε550 = 140 to 18 M-1 cm-1) when VanX was reacted with substrate, suggesting that the coordination number of the metal increases from 5 to 6 upon substrate binding. The stopped-flow trace was fitted to a kinetic mechanism that suggests the presence of an intermediate whose breakdown is rate-limiting. Rapid-freeze quench EPR studies verified the presence of a reaction intermediate that exhibits an unusually low hyperfine constant (33 G), which suggests a bidentate coordination of the intermediate to the metal center. The EPR studies also identified a distinct enzyme product complex. The results were used to offer a detailed reaction mechanism for VanX that can be used to guide future inhibitor design efforts

Notes on Succession in Old Fields in Southeastern Ontario: the Herbs

Vegetation in abandoned hayfields was monitored during 1976-1998. An earlier successional stage followed ploughing. Changes in tree, shrub and vine populations have been reported earlier and showed expected increases in species richness and cover. Highest species richness of herbs occurred three years after ploughing. Non-woody species richness trended irregularly downward, while non-woody cover was variable, peaking in 1987. Within the herbaceous community, year-to-year changes in cover and frequency of species in the following selected groups are reported here: 18 grasses including sown and adventive species; 13 legumes including two sown species; 14 macroforbs of the Compositae, including a goldenrod, Solidago canadensis, which dominated parts of the fields; a rosette weed, Taraxacum officinalis; sedges, horsetails and some other minor components. Grasses and goldenrods were grazed, sometimes intensively and repeatedly, by insects; grasses were impacted by skipper larvae (Thymelicus lineola), and goldenrods by beetle larvae (Trirhabda spp.). Effects of repeated outbreaks on host plant cover are shown for two plots (100 m2) matching the scale of outbreaks

Efficient adaptive multilevel stochastic Galerkin approximation using implicit a posteriori error estimation

Partial differential equations (PDEs) with inputs that depend on infinitely many parameters pose serious theoretical and computational challenges. Sophisticated numerical algorithms that automatically determine which parameters need to be activated in the approximation space in order to estimate a quantity of interest to a prescribed error tolerance are needed. For elliptic PDEs with parameter-dependent coefficients, stochastic Galerkin finite element methods (SGFEMs) have been well studied. Under certain assumptions, it can be shown that there exists a sequence of SGFEM approximation spaces for which the energy norm of the error decays to zero at a rate that is independent of the number of input parameters. However, it is not clear how to adaptively construct these spaces in a practical and computationally efficient way. We present a new adaptive SGFEM algorithm that tackles elliptic PDEs with parameter-dependent coefficients quickly and efficiently. We consider approximation spaces with a multilevel structure---where each solution mode is associated with a finite element space on a potentially different mesh---and use an implicit a posteriori error estimation strategy to steer the adaptive enrichment of the space. At each step, the components of the error estimator are used to assess the potential benefits of a variety of enrichment strategies, including whether or not to activate more parameters. No marking or tuning parameters are required. Numerical experiments for a selection of test problems demonstrate that the new method performs optimally in that it generates a sequence of approximations for which the estimated energy error decays to zero at the same rate as the error for the underlying finite element method applied to the associated parameter-free problem.Comment: 22 page

Playing with nonuniform grids

Numerical experiments with discretization methods on nonuniform grids are presented for the convection-diffusion equation. These show that the accuracy of the discrete solution is not very well predicted by the local truncation error. The diagonal entries in the discrete coefficient matrix give a better clue: the convective term should not reduce the diagonal. Also, iterative solution of the discrete set of equations is discussed. The same criterion appears to be favourable.

The University as a Gendered Organization: Effects on Management Type, Climate and Job Satisfaction

Numbers of women holding faculty positions in science, technology, engineering, and mathematics (STEM) remain low in university systems, despite gains women have made in achievement of advanced degrees. No one reason is clearly the culprit for the low numbers, though women in STEM have been shown to have more negative perceptions of climate, be more dissatisfied with their jobs, and have greater inclination to leave their positions than men. As males comprise a majority of STEM employees, the masculine-genderedness of these organizations may create a more dissatisfactory work environment for women. This may, in turn, have negative impact on the retention and promotion of women. The concept of genderedness has been defined by relative numbers of males, occupation type through language, and through the hierarchical nature of the bureaucratic organizational system. Both STEM disciplines and university environments have been considered gendered based on these definitions. One potential component that has not been strictly applied to gendered organizations is organization system management type. As female leaders tend to be more participative while male leaders tend to be more authoritative, this study proposed that measurements of organization system type could be utilized as an additional indication of organizational genderedness. In addition, the study proposed that more authoritative styles of management systems in gendered organizations would yield lower satisfaction and more negative climate perceptions for women. Faculty members from a comprehensive university were surveyed for their perceptions of system organization type, climate, and job satisfaction. Survey results were analyzed to determine if perceptions varied by gender, college type (STEM or non- STEM), rank, and organizational hierarchical level. The study determined that faculty perceived the system management type within ascending hierarchal university levels as increasingly more authoritative and that gendered colleges are perceived as more authoritative than non-gendered colleges. This may provide a new way to help define organizational genderedness. The study also found that correlation existed for both male and female faculty between perceptions of organizational system type and both climate and job satisfaction. However, the perception difference between genders was not significant enough to provide evidence for differential effects for women versus men