6,604 research outputs found

    Wireless Water Flow Meter Network in the Great Bay

    Get PDF
    The Oyster Restoration Program alongside the New Hampshire chapter of the Nature Conservancy is working towards developing new oyster beds throughout the Great Bay. Sedimentation is proving to be a vast problem by covering up the beds before they have a chance to grow to a healthy level. The many rivers entering the Great Bay are bringing the sediments from all over the region and limiting the ability of the program to develop the new beds. They need a way to measure the sedimentation rate, by measuring the flow rate of the rivers over a single tidal cycle in various locations throughout the bay. This is done simply by the design of a wireless water flow meter network. Using a Price Meter as the measurement tool and an Arduino UNO to organize the data, the Oyster Restoration Program can monitor the characteristics of the locations to gain a better understanding of the location as a potential site for a new oyster bed. The design of an self contained system to extract and store the data to be collected is essential to speed up the process of monitoring these locations, which the device developed here will do

    Extending Nunchaku to Dependent Type Theory

    Get PDF
    Nunchaku is a new higher-order counterexample generator based on a sequence of transformations from polymorphic higher-order logic to first-order logic. Unlike its predecessor Nitpick for Isabelle, it is designed as a stand-alone tool, with frontends for various proof assistants. In this short paper, we present some ideas to extend Nunchaku with partial support for dependent types and type classes, to make frontends for Coq and other systems based on dependent type theory more useful.Comment: In Proceedings HaTT 2016, arXiv:1606.0542

    The effect of toxic Microcystis aeruginosa on four different populations of Daphnia

    Get PDF
    Cyanobacteria reduce the fitness of many Daphnia species, and blooms in eutrophic lakes may place strong selective pressure upon these primary consumers. This study examines the ability of daphnids to resist the deleterious effects of toxic Microcystis and determine if this resistance is related to the trophic conditions of their native lakes. Three populations of Daphnia pulex/pulicaria were examined; D. pulicaria from eutrophic Klamath Lake in Oregon, D. pulex from eutrophic Old Durham Reservoir in New Hampshire, and D. pulicaria from oligotrophic Russell Pond in New Hampshire. D. carinata from meso-oligotrophic Lake Rotoaira in New Zealand was used as a known cyanobacteria-sensitive species. Ten-day old 5th-6th instar animals were exposed to a mixture of Microcystis aeruginosa and Chlorella vulgaris (25% and 100% M. aeruginosa). Body length, lipid index, reproductive index and clearance rate were assessed for each population after 120 hours of treatment. A feeding bioassay response quantifying the energetic (feeding rate) cost of post abdominal rejections was also determined for a gradient of M. aeruginosa concentrations from 0% to 100%. The four populations of Daphnia exhibited different rates of decline in overall fitness when exposed to Microcystis. Populations exposed to Microcystis exhibited reduced thoracic beat rate, lower lipid and reproductive indexes, and higher cost of post abdominal rejections in comparison to daphnids in the control Chlorella. Length was not a sensitive indicator of fitness level. D. pulex from eutrophic Klamath Lake had a mean clearance rate in 100% Microcystis that was three to four times higher than D. pulicaria from oligotrophic Russell Pond. In general, daphnids from oligotrophic lakes exhibited a more drastic decline in fitness than daphnids from eutrophic lakes. This suggests that taxonomically related populations of Daphnia have evolved a suite of adaptations to Microcystis depending upon their history of exposure

    Foundational Extensible Corecursion

    Full text link
    This paper presents a formalized framework for defining corecursive functions safely in a total setting, based on corecursion up-to and relational parametricity. The end product is a general corecursor that allows corecursive (and even recursive) calls under well-behaved operations, including constructors. Corecursive functions that are well behaved can be registered as such, thereby increasing the corecursor's expressiveness. The metatheory is formalized in the Isabelle proof assistant and forms the core of a prototype tool. The corecursor is derived from first principles, without requiring new axioms or extensions of the logic

    Bill Viola ou La mise en scène de la déroute

    Get PDF

    Our World Flipped Upside Down

    Get PDF
    During the past decade, there have been increasing discussions between the Financial Accounting Standard Board (FASB) and the International Accounting Standard Board (IASB) regarding the harmonization of United States Generally Accepted Accounting Principles (US GAAP) and International Financial Reporting Standards (IFRS). What used to be talk is now becoming a reality. On October 29, 2002 FASB and the International Accounting Standards Board (IASB) released the Memorandum of Understanding, which announced the significant steps that are being taken to converge the US and the International Accounting Standards. There are hopes for some parts of the convergence to be finalized by 2011, but in some areas it is still to be determined. This pending change in the United States (US) raises many important questions and concerns for companies currently using US GAAP for financial reporting. What are the differences between US GAAP and the IFRS? How will this change affect US firms? Many accounting professionals are not familiar with the differences between US GAAP and IFRS, and firms are starting to struggle with the technical and system changes needed to adopt IFRS. In addition, what are the implications to current accounting students

    THE ANTIPREDATOR BEHAVIORS OF CRYPTIC AND APOSEMATIC ANURANS AND VARIABILITY IN ALKALOIDS, CONSPICUOUSNESS, AND PATTERN WITHIN DENDROBATES AURATUS (DENDROBATIDAE)

    Get PDF
    Crypsis and aposematism are common antipredator strategies that have evolved as defensive mechanisms to prevent predation. Prey that employ these defensive strategies also exhibit antipredator behaviors meant to avoid or deter predation. These behaviors include: (1) escape or immobility in the presence of an immediate predator or (2) exhibiting bold behavior by accepting the risk of potential predation in a novel environment in exchange for the benefits of foraging and mating opportunities. In this study, the escape and bold behaviors of cryptic members of Craugastor and the aposematic dendrobatid Dendrobates auratus were tested to compare these alternative antipredator strategies. Craugastor behaved more cryptically and was less bold than D. auratus in response to simulated predators and when emerging from a cover object. Further, a human and bird model were used as simulated predators to compare the escape behaviors exhibited by Craugastor and D. auratus in response to each. The results of this study support previous findings that cryptic anurans commonly rely on immobility to maximize camouflage, whereas aposematic anurans exhibit movement that enhance their warning signals. Also, movements exhibited by D. auratus were distinctive based on the identity of the approaching predator, suggesting that predator type is important when studying the escape behavior of an aposematic species. Furthermore, although crypsis and aposematism are thought to be alternative strategies, a continuum ranging from cryptic to aposematic may exist within aposematic species. The color/pattern and alkaloid chemical defense of individual D. auratus were measured and compared to their antipredator behavior to establish a potential spectrum of antipredator strategies. Two populations of D. auratus were found to exhibit alternative antipredator strategies – the Atlantic population was more bold, conspicuous, and chemically defended than the Pacific population. The two populations of D. auratus support the possibility that crypsis and aposematism are not mutually exclusive. Instead, populations of D. auratus, in response to unique selective pressures, can utilize a combination of antipredator strategies including morphology and behavior
    • …
    corecore