Digital simulation for post-docking response

The digital program, 2BODY, which simulates the translational and rotational motion of two connected rigid bodies and provides both digital and plot output is described. Relative rotation of the bodies at the connection is allowed, thereby providing a model suitable for studying system stability and response during a soft-dock regime. A users manual for the program is given as well as all the details and background pertaining to the equations of motion and mathematical models, integration scheme, and input/output routines

Microgravity studies of aggregation in particulate clouds

Aggregation in clouds of submillimeter quartz and volcanic ash particles was studied in microgravity. Particle clouds generated by pulses of air immediately formed electrostatic filamentary aggregates upon cessation of air turbulence. Manual agitation of experiment chambers produced cm-size loose grain clusters which voraciously scavenged free-floating material in their vicinity. A dipole model accounts for these observations. Experimental results have ramifications for the behavior of natural cloud systems and primary accretion of solids in the early solar nebula

Strategic Institutional Choice: Voters, States, and Congressional Term Limits

This paper demonstrates that states’ decisions on limiting congressional terms are empirically determined by measures of relative political influence in Congress. States’ choices on term limits are quantified as a multiple-categorical variable that reflects variation in the stringency of term limits laws passed. Using 1992 data on the American states, the model controls for unobserved heterogeneity that is introduced by some voters having access to institutions of direct democracy. At 2002 state-level values for congressional tenure and federal spending, the model predicts approximately eight to ten additional states would choose to limit terms of their own congressional delegations, but are prohibited from doing so under a Supreme Court ruling. The results hold implications for institutional federalism and the potential passage of similar political institutions across the states.term limits; political institutions; federalism; political economy

Dividing the Indivisible: Procedures for Allocating Cabinet Ministries to Political Parties in a Parliamentary System

Political parties in Northern Ireland recently used a divisor method of apportionment to choose, in sequence, ten cabinet ministries. If the parties have complete information about each others' preferences, we show that it may not be rational for them to act sincerely by choosing their most-preferred ministry that is available. One consequence of acting sophisticatedly is that the resulting allocation may not be Pareto-optimal, making all the parties worse off. Another is nonmonotonicty—choosing earlier may hurt rather than help a party. We introduce a mechanism that combines sequential choices with a structured form of trading that results in sincere choices for two parties. Although there are difficulties in extending this mechanism to more than two parties, other approaches are explored, such as permitting parties to making consecutive choices not prescribed by an apportionment method. But certain problems, such as eliminating envy, remain.Proportional Representation, apportionment, divisor methods, Sincere and Sophisticated Choices, Envy Free Allocations, Sports Drafts

Portfolio Diversification, Leverage, and Financial Contagion

This paper studies the extent to which basic principles of portfolio diversification explain "contagious selling" of financial assets when there are purely local shocks (e.g., a financial crisis in one country). The paper demonstrates that elementary portfolio theory offers key insights into "contagion." Most important, portfolio diversification and leverage are sufficient to explain why an investor will find it optimal to significantly reduce all risky asset positions when an adverse shock impacts just one asset. This result does not depend on margin calls: it applies to portfolios and institutions that rely on borrowed funds. The paper also shows that Value-at-Risk portfolio management rules do not have significantly different consequences for portfolio rebalancing than a variety of other rules. Copyright 2000, International Monetary Fund

USING CALLING ACTIVITY TO PREDICT CALLING ACTIVITY: A CASE STUDY WITH THE ENDANGERED HOUSTON TOAD (BUFO [ANAXYRUS] HOUSTONENSIS)

Understanding anuran calling activity patterns is important for maximizing efficiency and value of call survey data collection and analyses. Previous studies have primarily focused on identifying and quantifying abiotic variables that influence anuran calling activity, and investigating relationships between calling activity and population estimates. In this study we investigated the use of a predictor pond approach to guide call survey effort. In this approach, calling activity at a subset of breeding sites (e.g., ponds) is used as a predictor of calling activity at additional breeding sites, with the goal being to minimize sampling effort while simultaneously maximizing sampling efficiency. We explored the efficiency of this approach using call survey data collected on the endangered Houston Toad (Bufo [Anaxyrus] houstonensis) at 15 known breeding ponds over 9 survey years. We found that if calling activity at 3 predictor ponds was used to decide if additional call surveys would occur at the remaining 12 ponds, we would have hypothetically correctly assumed calling activity was not occurring at non-predictor ponds on 92.1% of survey nights, and we would have hypothetically detected 93.9% of the total number of detected individuals over the 9 survey years. We found the predictor pond approach performed well in our case study, and believe it could be a valuable tool for many anuran monitoring programs

Rapid Design and Manufacture of Ultralight Cellular Materials

This paper details the design, manufacture and testing of regular metallic lattice structures with unit cell sizes in the range 0.8mm to 5mm and truss elements of 100-500 µm in diameter [1]. The structures were manufactured using Selective Laser Melting (SLM) technology from 316L stainless steel. Compression tests have shown yield loadings of over 3.5kN despite being only 18mm by 18mm by 10mm in height, the results are favourably comparable to current commercially available metallic foams. Software has been developed that creates slice files without the use of CAD software or STL files and is capable of producing lattices within a volume defined by a STL file.Mechanical Engineerin

Reformation in the diocese of Dunblane

The study of the Reformation as a religious and political movement within a particular diocese offers several attractions. A limited study in terms of ecclesiastical jurisdiction and organisation, it is able in greater detail to take into account the influence of the old church diocesan structure. Religious institutions within the diocese can as well be examined in terms of their local influence. Although the new church superintendent, John Wynram, supervised Fife and the other parts of Perthshire as well as Dunblane diocese, the diocesan structure of the old church, and the all important benefice revenues associated with that structure, remained intact long after 1560. To the extent that the new church clergy attempted to continue the cure of souls within the basic parochial structure they inherited from their predecessor, the diocese is a reasonable ecclesiastical unit within which to observe the functions of both churches. The political and religious activities of local lay families can be examined within this setting as well. Their acceptance or rejection of the Reformation would be particularly significant in a rural area such as Dunblane diocese, in the main removed from the powerful and persuasive pulpits of Edinburgh and the east coast. Several lairds and minor nobles within the diocese were heads of families whose adherence to the new church was essential for its local development. The attendance of many Protestant lairds at the Reformation parliament of 1560 has long been recognised as a significant indicator of support for the Reformation by the rural gentry, but the influence of these men within their local surroundings has been less studied

A Simple Bargaining Mechanism That Elicits Truthful Reservation Prices

We describe a simple 2-stage mechanism that induces two bargainers to be truthful in reporting their reservation prices in a 1st stage. If these prices criss-cross, the referee reports that they overlap, and the bargainers proceed to make offers in a 2nd stage. The average of the 2nd-stage offers becomes the settlement if both offers fall into the overlap interval; if only one offer falls into this interval, it is the settlement, but is implemented with probability 1/2; if neither offer falls into the interval, there is no settlement. Thus, if the bargainers reach the 2nd stage, they know their reservation prices overlap even if they fail to reach a settlement, possibly motivating them to try again.Bargaining; truth-telling mechanisms; probabilistic implementation; incomplete information.

The South Dakota cooperative land use effort: A state level remote sensing demonstration project

Remote sensing technology can satisfy or make significant contributions toward satisfying many of the information needs of governmental natural resource planners and policy makers. Recognizing this potential, the South Dakota State Planning Bureau and the EROS Data Center together formulated the framework for an ongoing Land Use and Natural Resource Inventory and Information System Program. Statewide land use/land cover information is generated from LANDSAT digital data and high altitude photography. Many applications of the system are anticipated as it evolves and data are added from more conventional sources. The conceptualization, design, and implementation of the program are discussed