Hamiltonian mappings and circle packing phase spaces: numerical investigations

In a previous paper we introduced examples of Hamiltonian mappings with phase space structures resembling circle packings. We now concentrate on one particular mapping and present numerical evidence which supports the conjecture that the set of circular resonance islands is dense in phase space.Comment: 9 pages, 2 figure

The Ecology of the Timber Rattlesnake (\u3ci\u3eCrotalus horridus\u3c/i\u3e) in Southeastern Virginia

Few studies have examined the relationship between forest canopy structure and the ecology of the timber rattlesnake (Crotalus horridus). I used radiotelemetry to compare the movements, activity range sizes and behaviors of timber rattlesnakes before and after a large-scale natural disturbance that opened a previously closed canopy. The disturbance was Hurricane Isabel which made landfall in northeast North Carolina and southeastern Virginia in 2003. Isabel created gaps in the canopy through tree blowdown, resulting in a 16.6% opening in the forest canopy at my study site, in southeastern Virginia. I compared six years of female tracking data from before Isabel to two years of data on females after Isabel. There was no difference in the mean total distance moved, mean distance per day, mean range length, or the greatest mean maximum distance traveled from hibernaculum. However, the mean distance per movement was significantly longer after Isabel. All activity ranges (minimum convex polygon and the 25%, 50%, 75% and 95% kernel isopleths) were significantly smaller after Isabel. Further, following Isabel a greater proportion of behavioral events, including ecdysis and courtship, occurred within the forest as opposed to anthropogenic areas. I also conducted a dietary study covering both tracking periods and found gray squirrels (Sciurus carolinensis) to be the most commonly consumed prey item (45.0%), followed by hispid cotton rats (Sigmodon hispidus; 20.0%), and birds (12.5%)

The influence of defects of the fatigue resistance of butt and girth welds in A106B steel

This three-phase study was directed at developing a fitness for service defect acceptance criteria for welds with defect indications. The study focussed on A106 Gr. B steel pipe. The first phase involved a literature search and critical review to develop the preliminary acceptance criteria to the extent permitted by the data. The second phase developed data for flat plate, wall segment, and vessel specimens containing artificial or natural planar or volumetric defects. The final phase developed acceptance criteria from the test data

Enforcing Promises: An Examination of the Basis of Contract

The obligation to keep promises is a commonly acknowledged moral duty. Yet not all promises – however solemnly vowed – are enforceable at law. Why are some promises legally binding and others not? Orthodox doctrinal categories provide only modest assistance in answering this persistent question. Conventional analysis, for example, has distinguished promises made in exchange for a return promise or performance from nonreciprocal promises. Indeed, common law bargain theory is classically simple: bargained-for promises are presumptively enforceable; nonreciprocal promises are presumptively unenforceable. But this disarmingly simple theory has never mirrored reality. Contract law has ventured far beyond such narrow limitations, embracing reliance and unjust enrichment as additional principles of promissory obligation. Thus, a promise may be enforceable to the extent that the promisee has incurred substantial costs, or conferred benefits, in reasonable reliance on the promise. Promissory estoppel under Section 90 of the Restatement of Contracts is the primary enforcement mechanism when action in reliance follows the promise. If the change of position by the promisee precedes the promise, its nexus with the promise is more subtle. For example, a promise is enforceable when it follows a non-donative material benefit conferred by the promisee. Unjust enrichment principles are typically invoked to enforce such past consideration promises. Despite this expansion of liability, gratuitous promises of gifts or unilateral pledges to confer benefits remain legally unenforceable

Liquidated Damages, Penalties and the Just Compensation Principle: Some Notes on an Enforcement Model and a Theory of Efficient Breach

Part I of this Article examines the role of liquidated damage provisions and penalties in the context of a general theory of efficient breach of contract. The proof problems inherent in fully recovering idiosyncratic values within the context of operationally practical damage sanctions may prevent the non-breaching party from recovering his subjective expectations if recovery is limited to legally determined remedies. The expected cost of establishing true losses under conventional damage measures will thus induce parties who face uncertain or nonprovable anticipated losses to negotiate stipulated damage agreements. The current penalty rule subjects these agreements to costly review, based not on the fairness of the process, but on whether the initial estimate sufficiently mirrors the anticipated provable loss. Part II examines the hypothesis that, absent evidence of process unfairness in bargaining, efficiency will be enhanced by the enforcement of an agreed allocation of risks embodied in a liquidated damage clause. We argue that agreed damage measures and in terrorem provisions represent, under many circumstances, the most efficient means by which parties can insure against the otherwise non-compensable consequences of breach. Our hypothesis is then also tested against a series of conditions in order to identify alternative legal principles that may provide less costly means of avoiding the harmful effects whose perception apparently prompted the current penalty rule

Measuring Sellers\u27 Damages: The Lost-Profits Puzzle

A buyer repudiates a fixed-price contract to purchase goods, and the seller sues for damages. How should a court measure the seller\u27s loss? The answer seems simple: The seller should be awarded damages sufficient to place it in the same economic position it would have enjoyed had the buyer performed the contract. But the seductive conceptual simplicity of the compensation principle disguises substantial practical problems in measuring seller\u27s damages. Contract law has traditionally minimized measurement difficulties by basing damages in most cases on the difference between the contract price and market value of the repudiated goods. The common law courts generally limited the seller to such market damages whenever the seller had a resale market for the contract goods. These courts assumed that combining this damage award with proceeds from a resale would give the seller the profits that performance would have earned it

The Mitigation Principle: Toward a General Theory of Contractual Obligation

The duty to mitigate is a universally accepted principle of contract law requiring that each party exert reasonable efforts to minimize losses whenever intervening events impede contractual objectives. Although applications of the mitigation principle pervade the specific rules of contract, it is startling how many questions remain unanswered as to precisely what efforts the mitigation duty requires and what point in time the obligation arises. For example, under what circumstances does mitigation require an injured party to deal with the contract breacher? Why does the duty to minimize losses mature only after the breach, even if the injured party became aware much earlier of a significant danger of breach and had a cost-effective opportunity to mitigate the prospective loss? Is the duty to communicate special or unforeseeable circumstances confined to the time of contracting, even where the communication of post-contract but pre-performance information might reduce costs? These and many similar questions remain unresolved because the relationship among the diverse rules of mitigation has not been systematically articulated. Recognizing that each party\u27s mitigation responsibility is inextricably linked to the performance obligation of his contracting partner is the key step in fitting the mitigation principle into a general theory of contractual obligation. In recent years, a maturing theoretical scholarship has furthered understanding of the performance and remedial obligations of contracting parties. By focusing on particular performance problems, this scholarship has not only uncovered further questions but also heightened interest in a theoretical formulation that weaves the performance and remedial rules of contract into a single fabric

The Limits of Expanded Choice: An Analysis of the Interactions between Express and Implied Contract Terms

Although trade and its defining terms lie at the very core of contract law, perceptions of the state\u27s involvement in the exchange process remain peculiarly incomplete. Everyone understands that the state supplies the fundamental property-defining rules for pre-trade endowments. For instance, governmentally provided rules of tort, nuisance, and civil rights establish basic boundaries of what initially belongs to an individual and, hence, what he has to offer in exchange. When an exchange subsequently takes place, however, the parties themselves assume an important part of the burden of communicating what rights are being given and received. Although the state\u27s general rules of contract provide a set of standard gap-filling assumptions or implied terms, almost every agreement requires the parties to provide some additional individualized content. At one level, the private and state-supplied terms of an executory contract represent an attempted interparty communication of the substantive entitlements intended to be exchanged. Since, however; the terms communicate evidence of the exchange\u27s content to the state as well, they also constitute the principal legal definition of the rights reallocation. Unfortunately, this definitional process requires parties to employ inherently error-prone signals – the formulations of their agreement. If the chosen combination of privately and publicly supplied terms results in an inappropriate formulation, a party may suffer a costly surprise when the contract is legally enforced. The disappointed party will frequently contend that the content of the contract, as ultimately interpreted, does not accurately describe the original intent or expectation. Many such complaints about the misformulation or misinterpretation of an agreement are rooted in tensions between implied and express terms and between standard and unconventional forms of expression. To the extent that these tensions have been understood at all, the major attempt to harmonize them relies on what we term the Expanded Choice postulate. The postulate maintains that implied terms expand contractors\u27 choices by providing standardized and widely suitable preformulations, thus eliminating the cost of negotiating every detail of the proposed arrangement. This Expanded Choice thesis implicitly presumes a neutral policy toward individualized agreements: atypical parties lose nothing, since they remain unrestrained from designing customized provisions to replace the state-supplied terms

Enforcing Promises: An Examination of the Basis of Contract

The obligation to keep promises is a commonly acknowledged moral duty. Yet not all promises – however solemnly vowed – are enforceable at law. Why are some promises legally binding and others not? Orthodox doctrinal categories provide only modest assistance in answering this persistent question. Conventional analysis, for example, has distinguished promises made in exchange for a return promise or performance from nonreciprocal promises. Indeed, common law bargain theory is classically simple: bargained-for promises are presumptively enforceable; nonreciprocal promises are presumptively unenforceable. But this disarmingly simple theory has never mirrored reality. Contract law has ventured far beyond such narrow limitations, embracing reliance and unjust enrichment as additional principles of promissory obligation. Thus, a promise may be enforceable to the extent that the promisee has incurred substantial costs, or conferred benefits, in reasonable reliance on the promise. Promissory estoppel under Section 90 of the Restatement of Contracts is the primary enforcement mechanism when action in reliance follows the promise. If the change of position by the promisee precedes the promise, its nexus with the promise is more subtle. For example, a promise is enforceable when it follows a non-donative material benefit conferred by the promisee. Unjust enrichment principles are typically invoked to enforce such past consideration promises. Despite this expansion of liability, gratuitous promises of gifts or unilateral pledges to confer benefits remain legally unenforceable

Ten year change in forest succession and composition measured by remote sensing

Vegetation dynamics and changes in ecological patterns were measured by remote sensing over a 10 year period (1973 to 1983) for 148,406 landscape elements, covering more than 500 sq km in a protected forested wilderness. Quantitative measurements were made possible by methods to detect ecologically meaningful landscape units; these allowed measurement of ecological transition frequencies and calculation of expected recurrence times. Measured ecological transition frequencies reveal boreal forest wilderness as spatially heterogeneous and highly dynamic, with one-sixth of the area in clearings and early successional stages, consistent with recent postulates about the spatial and temporal patterns of natural ecosystems. Differences between managed forest areas and a protected wilderness allow assessment of different management regimes