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Sample records for double auction mechanism

  1. Statistical theory of the continuous double auction

    NASA Astrophysics Data System (ADS)

    Smith, Eric; Doyne Farmer, J.; Gillemot, László; Krishnamurthy, Supriya

    2003-12-01

    Most modern financial markets use a continuous double auction mechanism to store and match orders and facilitate trading. In this paper we develop a microscopic dynamical statistical model for the continuous double auction under the assumption of IID random order flow, and analyse it using simulation, dimensional analysis, and theoretical tools based on mean field approximations. The model makes testable predictions for basic properties of markets, such as price volatility, the depth of stored supply and demand versus price, the bid-ask spread, the price impact function, and the time and probability of filling orders. These predictions are based on properties of order flow and the limit order book, such as share volume of market and limit orders, cancellations, typical order size, and tick size. Because these quantities can all be measured directly there are no free parameters. We show that the order size, which can be cast as a non-dimensional granularity parameter, is in most cases a more significant determinant of market behaviour than tick size. We also provide an explanation for the observed highly concave nature of the price impact function. On a broader level, this work suggests how stochastic models based on zero intelligence agents may be useful to probe the structure of market institutions. Like the model of perfect rationality, a stochastic zero intelligence model can be used to make strong predictions based on a compact set of assumptions, even if these assumptions are not fully believable.

  2. Poisson-process generalization for the trading waiting-time distribution in a double-auction mechanism

    NASA Astrophysics Data System (ADS)

    Cincotti, Silvano; Ponta, Linda; Raberto, Marco; Scalas, Enrico

    2005-05-01

    In this paper, empirical analyses and computational experiments are presented on high-frequency data for a double-auction (book) market. Main objective of the paper is to generalize the order waiting time process in order to properly model such empirical evidences. The empirical study is performed on the best bid and best ask data of 7 U.S. financial markets, for 30-stock time series. In particular, statistical properties of trading waiting times have been analyzed and quality of fits is evaluated by suitable statistical tests, i.e., comparing empirical distributions with theoretical models. Starting from the statistical studies on real data, attention has been focused on the reproducibility of such results in an artificial market. The computational experiments have been performed within the Genoa Artificial Stock Market. In the market model, heterogeneous agents trade one risky asset in exchange for cash. Agents have zero intelligence and issue random limit or market orders depending on their budget constraints. The price is cleared by means of a limit order book. The order generation is modelled with a renewal process. Based on empirical trading estimation, the distribution of waiting times between two consecutive orders is modelled by a mixture of exponential processes. Results show that the empirical waiting-time distribution can be considered as a generalization of a Poisson process. Moreover, the renewal process can approximate real data and implementation on the artificial stocks market can reproduce the trading activity in a realistic way.

  3. Understanding Financial Market States Using an Artificial Double Auction Market.

    PubMed

    Yim, Kyubin; Oh, Gabjin; Kim, Seunghwan

    2016-01-01

    The ultimate value of theories describing the fundamental mechanisms behind asset prices in financial systems is reflected in the capacity of such theories to understand these systems. Although the models that explain the various states of financial markets offer substantial evidence from the fields of finance, mathematics, and even physics, previous theories that attempt to address the complexities of financial markets in full have been inadequate. We propose an artificial double auction market as an agent-based model to study the origin of complex states in financial markets by characterizing important parameters with an investment strategy that can cover the dynamics of the financial market. The investment strategies of chartist traders in response to new market information should reduce market stability based on the price fluctuations of risky assets. However, fundamentalist traders strategically submit orders based on fundamental value and, thereby stabilize the market. We construct a continuous double auction market and find that the market is controlled by the proportion of chartists, Pc. We show that mimicking the real state of financial markets, which emerges in real financial systems, is given within the range Pc = 0.40 to Pc = 0.85; however, we show that mimicking the efficient market hypothesis state can be generated with values less than Pc = 0.40. In particular, we observe that mimicking a market collapse state is created with values greater than Pc = 0.85, at which point a liquidity shortage occurs, and the phase transition behavior is described at Pc = 0.85.

  4. Double-Auction Market Simulation Software for Very Large Classes

    ERIC Educational Resources Information Center

    Ironside, Brian; Joerding, Wayne; Kuzyk, Pat

    2004-01-01

    The authors provide a version of a double-auction market simulation designed for classes too large for most computer labs to accommodate in one sitting. Instead, students play the game from remote computers, wherever they may be and at any time during a given time period specified by the instructor. When the window of time expires, students can…

  5. Understanding Financial Market States Using an Artificial Double Auction Market

    PubMed Central

    2016-01-01

    The ultimate value of theories describing the fundamental mechanisms behind asset prices in financial systems is reflected in the capacity of such theories to understand these systems. Although the models that explain the various states of financial markets offer substantial evidence from the fields of finance, mathematics, and even physics, previous theories that attempt to address the complexities of financial markets in full have been inadequate. We propose an artificial double auction market as an agent-based model to study the origin of complex states in financial markets by characterizing important parameters with an investment strategy that can cover the dynamics of the financial market. The investment strategies of chartist traders in response to new market information should reduce market stability based on the price fluctuations of risky assets. However, fundamentalist traders strategically submit orders based on fundamental value and, thereby stabilize the market. We construct a continuous double auction market and find that the market is controlled by the proportion of chartists, Pc. We show that mimicking the real state of financial markets, which emerges in real financial systems, is given within the range Pc = 0.40 to Pc = 0.85; however, we show that mimicking the efficient market hypothesis state can be generated with values less than Pc = 0.40. In particular, we observe that mimicking a market collapse state is created with values greater than Pc = 0.85, at which point a liquidity shortage occurs, and the phase transition behavior is described at Pc = 0.85. PMID:27031110

  6. Understanding Financial Market States Using an Artificial Double Auction Market.

    PubMed

    Yim, Kyubin; Oh, Gabjin; Kim, Seunghwan

    2016-01-01

    The ultimate value of theories describing the fundamental mechanisms behind asset prices in financial systems is reflected in the capacity of such theories to understand these systems. Although the models that explain the various states of financial markets offer substantial evidence from the fields of finance, mathematics, and even physics, previous theories that attempt to address the complexities of financial markets in full have been inadequate. We propose an artificial double auction market as an agent-based model to study the origin of complex states in financial markets by characterizing important parameters with an investment strategy that can cover the dynamics of the financial market. The investment strategies of chartist traders in response to new market information should reduce market stability based on the price fluctuations of risky assets. However, fundamentalist traders strategically submit orders based on fundamental value and, thereby stabilize the market. We construct a continuous double auction market and find that the market is controlled by the proportion of chartists, Pc. We show that mimicking the real state of financial markets, which emerges in real financial systems, is given within the range Pc = 0.40 to Pc = 0.85; however, we show that mimicking the efficient market hypothesis state can be generated with values less than Pc = 0.40. In particular, we observe that mimicking a market collapse state is created with values greater than Pc = 0.85, at which point a liquidity shortage occurs, and the phase transition behavior is described at Pc = 0.85. PMID:27031110

  7. Statistical mechanics of budget-constrained auctions

    NASA Astrophysics Data System (ADS)

    Altarelli, F.; Braunstein, A.; Realpe-Gomez, J.; Zecchina, R.

    2009-07-01

    Finding the optimal assignment in budget-constrained auctions is a combinatorial optimization problem with many important applications, a notable example being in the sale of advertisement space by search engines (in this context the problem is often referred to as the off-line AdWords problem). On the basis of the cavity method of statistical mechanics, we introduce a message-passing algorithm that is capable of solving efficiently random instances of the problem extracted from a natural distribution, and we derive from its properties the phase diagram of the problem. As the control parameter (average value of the budgets) is varied, we find two phase transitions delimiting a region in which long-range correlations arise.

  8. Auction Mechanism to Allocate Air Traffic Control Slots

    NASA Technical Reports Server (NTRS)

    Raffarin, Marianne

    2003-01-01

    This article deals with an auction mechanism for airspace slots, as a means of solving the European airspace congestion problem. A disequilibrium, between Air Traffic Control (ATC) services supply and ATC services demand are at the origin of almost one fourth of delays in the air transport industry in Europe. In order to tackle this congestion problem, we suggest modifying both pricing and allocation of ATC services, by setting up an auction mechanism. Objects of the auction will be the right for airlines to cross a part of the airspace, and then to benefit from ATC services over a period corresponding to the necessary time for the crossing. Allocation and payment rules have to be defined according to the objectives of this auction. The auctioneer is the public authority in charge of ATC services, whose aim is to obtain an efficient allocation. Therefore, the social value will be maximized. Another objective is to internalize congestion costs. To that end, we apply the principle of Clarke-Groves mechanism auction: each winner has to pay the externalities imposed on other bidders. The complex context of ATC leads to a specific design for this auction.

  9. Adaptive Sniping for Volatile and Stable Continuous Double Auction Markets

    NASA Astrophysics Data System (ADS)

    Toft, I. E.; Bagnall, A. J.

    This paper introduces a new adaptive sniping agent for the Continuous Double Auction. We begin by analysing the performance of the well known Kaplan sniper in two extremes of market conditions. We generate volatile and stable market conditions using the well known Zero Intelligence-Constrained agent and a new zero-intelligence agent Small Increment (SI). ZI-C agents submit random but profitable bids/offers and cause high volatility in prices and individual trader performance. Our new zero-intelligence agent, SI, makes small random adjustments to the outstanding bid/offer and hence is more cautious than ZI-C. We present results for SI in self-play and then analyse Kaplan in volatile and stable markets. We demonstrate that the non-adaptive Kaplan sniper can be configured to suit either market conditions, but no single configuration is performs well across both market types. We believe that in a dynamic auction environment where current or future market conditions cannot be predicted a viable sniping strategy should adapt its behaviour to suit prevailing market conditions. To this end, we propose the Adaptive Sniper (AS) agent for the CDA. AS traders classify sniping opportunities using a statistical model of market activity and adjust their classification thresholds using a Widrow-Hoff adapted search. Our AS agent requires little configuration, and outperforms the original Kaplan sniper in volatile and stable markets, and in a mixed trader type scenario that includes adaptive strategies from the literature.

  10. Modeling and simulation of a double auction artificial financial market

    NASA Astrophysics Data System (ADS)

    Raberto, Marco; Cincotti, Silvano

    2005-09-01

    We present a double-auction artificial financial market populated by heterogeneous agents who trade one risky asset in exchange for cash. Agents issue random orders subject to budget constraints. The limit prices of orders may depend on past market volatility. Limit orders are stored in the book whereas market orders give immediate birth to transactions. We show that fat tails and volatility clustering are recovered by means of very simple assumptions. We also investigate two important stylized facts of the limit order book, i.e., the distribution of waiting times between two consecutive transactions and the instantaneous price impact function. We show both theoretically and through simulations that if the order waiting times are exponentially distributed, even trading waiting times are also exponentially distributed.

  11. Ergodic transition in a simple model of the continuous double auction.

    PubMed

    Radivojević, Tijana; Anselmi, Jonatha; Scalas, Enrico

    2014-01-01

    We study a phenomenological model for the continuous double auction, whose aggregate order process is equivalent to two independent M/M/1 queues. The continuous double auction defines a continuous-time random walk for trade prices. The conditions for ergodicity of the auction are derived and, as a consequence, three possible regimes in the behavior of prices and logarithmic returns are observed. In the ergodic regime, prices are unstable and one can observe a heteroskedastic behavior in the logarithmic returns. On the contrary, non-ergodicity triggers stability of prices, even if two different regimes can be seen.

  12. Ergodic Transition in a Simple Model of the Continuous Double Auction

    PubMed Central

    Radivojević, Tijana; Anselmi, Jonatha; Scalas, Enrico

    2014-01-01

    We study a phenomenological model for the continuous double auction, whose aggregate order process is equivalent to two independent queues. The continuous double auction defines a continuous-time random walk for trade prices. The conditions for ergodicity of the auction are derived and, as a consequence, three possible regimes in the behavior of prices and logarithmic returns are observed. In the ergodic regime, prices are unstable and one can observe a heteroskedastic behavior in the logarithmic returns. On the contrary, non-ergodicity triggers stability of prices, even if two different regimes can be seen. PMID:24558377

  13. Competitive Financing Mechanisms: Auctions Used by Federal Agencies.

    ERIC Educational Resources Information Center

    Joyner, Carlotta C.

    This report reviews auctions used by various federal agencies to examine the feasibility of using similar auctions to determine interest rates for student borrowing through the Federal Family Education Loan Program (FFELP) and the William D. Ford Federal Direct Loan Program. The review identified 31 different auctions, divided into two major…

  14. A False-name-Proof Double Auction Protocol for Arbitrary Evaluation Values

    NASA Astrophysics Data System (ADS)

    Sakurai, Yuko; Yokoo, Makoto

    We develop a new false-name-proof double auction protocol called the Generalized Threshold Price Double auction (GTPD) protocol. False-name-proofness generalizes strategy-proofness by incorporating the possibility of false-name bids, e.g., bids submitted using multiple e-mail addresses. An existing protocol called TPD protocol is false-name-proof but can handle only the cases where marginal utilities of each agent always decrease, while our new GTPD protocol can handle arbitrary evaluation values. When marginal utilities can increase, some bids cannot be divided into a single unit (e.g., an all-or-nothing bid). Due to the existence of such indivisible bids, meeting supply/demand becomes difficult. Furthermore, a seller/buyer can submit a false-name-bid by pretending to be a potential buyer/seller to manipulate allocations and payments. In the GTPD protocol, the auctioneer is required to absorb the supply-demand imbalance up to a given upper-bound. Also, the GTPD incorporate a new false-name-proof one-sided auction protocol that is guaranteed to sell/buy a certain number of units. Simulation results show that when the threshold price is set appropriately, this protocol can obtain a good social surplus, and the number of absorbed units is much smaller than the given upper-bound.

  15. Learning Based Bidding Strategy for HVAC Systems in Double Auction Retail Energy Markets

    SciTech Connect

    Sun, Yannan; Somani, Abhishek; Carroll, Thomas E.

    2015-07-01

    In this paper, a bidding strategy is proposed using reinforcement learning for HVAC systems in a double auction market. The bidding strategy does not require a specific model-based representation of behavior, i.e., a functional form to translate indoor house temperatures into bid prices. The results from reinforcement learning based approach are compared with the HVAC bidding approach used in the AEP gridSMART® smart grid demonstration project and it is shown that the model-free (learning based) approach tracks well the results from the model-based behavior. Successful use of model-free approaches to represent device-level economic behavior may help develop similar approaches to represent behavior of more complex devices or groups of diverse devices, such as in a building. Distributed control requires an understanding of decision making processes of intelligent agents so that appropriate mechanisms may be developed to control and coordinate their responses, and model-free approaches to represent behavior will be extremely useful in that quest.

  16. Alternative implementations of electric power auctions

    SciTech Connect

    Dekrajangpetch, S.; Sheble, G.B.

    1998-12-31

    Auctions are considered pricing mechanism of choice for the competitive electric power market. This paper outlines alternative structures for auction implementation. The issue of choosing between single-sided and double-sided auctions is discussed in this paper. To ensure the reliability of the power system, some ancillary services must be provided. this paper addresses various issues of ancillary services; for example, which ancillary services should be bundled and which should be unbundled (i.e., traded under separate contracts). Previous research has indicated that auctions can be formulated as a linear program and this linear program can be solved efficiently. However, when mixed integer solutions are required, it may be impossible to formulate the problem as a linear program. The authors discuss factors concerning this problem and attempt to identify whether auctions are required to implement as a mixed integer program.

  17. Mechanism Design for Multi-slot Ads Auction in Sponsored Search Markets

    NASA Astrophysics Data System (ADS)

    Deng, Xiaotie; Sun, Yang; Yin, Ming; Zhou, Yunhong

    In this paper, we study pricing models for multi-slot advertisements, where advertisers can bid to place links to their sales webpages at one or multiple slots on a webpage, called the multi-slot AD auction problem. We develop and analyze several important mechanisms, including the VCG mechanism for multi-slot ads auction, the optimal social welfare solution, as well as two weighted GSP-like protocols (mixed and hybrid). Furthermore, we consider that forward-looking Nash equilibrium and prove its existence in the weighted GSP-like pricing protocols.

  18. A novel method for strategy acquisition and its application to a double-auction market game.

    PubMed

    Phelps, Steve; McBurney, Peter; Parsons, Simon

    2010-06-01

    We introduce a method for strategy acquisition in nonzero-sum n -player games and empirically validate it by applying it to a well-known benchmark problem in this domain, namely, the double-auction market. Many existing approaches to strategy acquisition focus on attempting to find strategies that are robust in the sense that they are good all-round performers against all-comers. We argue that, in many economic and multiagent scenarios, the robustness criterion is inappropriate; in contrast, our method focuses on searching for strategies that are likely to be adopted by participating agents, which is formalized as the size of a strategy's basins of attraction under the replicator dynamics. PMID:19906587

  19. Comparisons of auction mechanisms in a multiple unit setting: A consideration for restructuring electric power markets

    NASA Astrophysics Data System (ADS)

    Bernard, John Charles

    The objective of this study was to compare the performance of five single sided auctions that could be used in restructured electric power markets across different market sizes in a multiple unit setting. Auction selection would profoundly influence an industry over $200 billion in size in the United States, and the consequences of implementing an inappropriate mechanism would be great. Experimental methods were selected to analyze the auctions. Two rounds of experiments were conducted, the first testing the sealed offer last accepted offer (LAO) and first rejected offer (FRO), and the clock English (ENG) and sealed offer English (SOE) in markets of sizes two and six. The FRO, SOE, and ENG used the same pricing rule. Second round testing was on the LAO, FRO, and the nonuniform price multiple unit Vickrey (MUV) in markets of sizes two, four, and six. Experiments lasted 23 and 75 periods for rounds 1 and 2 respectively. Analysis of variance and contrast analysis were used to examine the data. The four performance measures used were price, efficiency, profits per unit, and supply revelation. Five basic principles were also assessed: no sales at losses, all low cost capacity should be offered and sold, no high cost capacity should sell, and the market should clear. It was expected group size and auction type would affect performance. For all performance measures, group size was a significant variable, with smaller groups showing poorer performance. Auction type was significant only for the efficiency performance measure, where clock auctions outperformed the others. Clock auctions also proved superior for the first four principles. The FRO performed poorly in almost all situations, and should not be a preferred mechanism in any market. The ENG was highly efficient, but expensive for the buyer. The SOE appeared superior to the FRO and ENG. The clock improves efficiency over the FRO while less information kept prices under the ENG. The MUV was superior in revealing costs

  20. Emergence of Cooperative Long-Term Market Loyalty in Double Auction Markets.

    PubMed

    Alorić, Aleksandra; Sollich, Peter; McBurney, Peter; Galla, Tobias

    2016-01-01

    Loyal buyer-seller relationships can arise by design, e.g. when a seller tailors a product to a specific market niche to accomplish the best possible returns, and buyers respond to the dedicated efforts the seller makes to meet their needs. We ask whether it is possible, instead, for loyalty to arise spontaneously, and in particular as a consequence of repeated interaction and co-adaptation among the agents in a market. We devise a stylized model of double auction markets and adaptive traders that incorporates these features. Traders choose where to trade (which market) and how to trade (to buy or to sell) based on their previous experience. We find that when the typical scale of market returns (or, at fixed scale of returns, the intensity of choice) become higher than some threshold, the preferred state of the system is segregated: both buyers and sellers are segmented into subgroups that are persistently loyal to one market over another. We characterize the segregated state analytically in the limit of large markets: it is stabilized by some agents acting cooperatively to enable trade, and provides higher rewards than its unsegregated counterpart both for individual traders and the population as a whole. PMID:27120473

  1. Emergence of Cooperative Long-Term Market Loyalty in Double Auction Markets

    PubMed Central

    Alorić, Aleksandra; Sollich, Peter; McBurney, Peter; Galla, Tobias

    2016-01-01

    Loyal buyer-seller relationships can arise by design, e.g. when a seller tailors a product to a specific market niche to accomplish the best possible returns, and buyers respond to the dedicated efforts the seller makes to meet their needs. We ask whether it is possible, instead, for loyalty to arise spontaneously, and in particular as a consequence of repeated interaction and co-adaptation among the agents in a market. We devise a stylized model of double auction markets and adaptive traders that incorporates these features. Traders choose where to trade (which market) and how to trade (to buy or to sell) based on their previous experience. We find that when the typical scale of market returns (or, at fixed scale of returns, the intensity of choice) become higher than some threshold, the preferred state of the system is segregated: both buyers and sellers are segmented into subgroups that are persistently loyal to one market over another. We characterize the segregated state analytically in the limit of large markets: it is stabilized by some agents acting cooperatively to enable trade, and provides higher rewards than its unsegregated counterpart both for individual traders and the population as a whole. PMID:27120473

  2. Efficient Nash Equilibrium Resource Allocation Based on Game Theory Mechanism in Cloud Computing by Using Auction.

    PubMed

    Nezarat, Amin; Dastghaibifard, G H

    2015-01-01

    One of the most complex issues in the cloud computing environment is the problem of resource allocation so that, on one hand, the cloud provider expects the most profitability and, on the other hand, users also expect to have the best resources at their disposal considering the budget constraints and time. In most previous work conducted, heuristic and evolutionary approaches have been used to solve this problem. Nevertheless, since the nature of this environment is based on economic methods, using such methods can decrease response time and reducing the complexity of the problem. In this paper, an auction-based method is proposed which determines the auction winner by applying game theory mechanism and holding a repetitive game with incomplete information in a non-cooperative environment. In this method, users calculate suitable price bid with their objective function during several round and repetitions and send it to the auctioneer; and the auctioneer chooses the winning player based the suggested utility function. In the proposed method, the end point of the game is the Nash equilibrium point where players are no longer inclined to alter their bid for that resource and the final bid also satisfies the auctioneer's utility function. To prove the response space convexity, the Lagrange method is used and the proposed model is simulated in the cloudsim and the results are compared with previous work. At the end, it is concluded that this method converges to a response in a shorter time, provides the lowest service level agreement violations and the most utility to the provider.

  3. A Centralized Auction Mechanism for the Disability and Survivors Insurance in Chile

    NASA Astrophysics Data System (ADS)

    Reyes H., Gonzalo

    As part of the pension reform recently approved in Chile, the government introduced a centralized auction mechanism to provide the Disability and Survivors (D&S) Insurance that covers recent contributors among the more than 8 million participants in the mandatory private pension system. This paper is intended as a case study presenting the main distortions found in the decentralized operation of the system that led to this reform and the challenges faced when designing a competitive auction mechanism to be implemented jointly by the Pension Fund Managers (AFP). In a typical bilateral contract the AFP retained much of the risk and the Insurance Company acted in practice as a reinsurer. The process to hire this contract was not competitive and colligated companies ended up providing the service. Several distortions affected competition in the market through incentives to cream-skim members by AFPs (since they bear most of the risk) or efforts to block disability claims. Since the price of this insurance is hidden in the fees charged by AFPs for the administration of individual accounts and pension funds there was lack of price transparency. Since new AFPs have no history of members’ disability and mortality profile the insurance contract acted as a barrier to entry in the market of AFP services, especially when D&S insurance costs reached 50% of total costs. Cross-subsidies between members of the same AFP, inefficient risk pooling (due to pooling occurring at the AFP rather than at the system level) and regulatory arbitrage, since AFPs provided insurance not being regulated as an insurance company, were also present. A centralized auction mechanism solves these market failures, but also gives raise to new challenges, such as how to design a competitive auction that attracts participation and deters collusion. Design features that were incorporated in the regulation to tackle these issues, such as dividing coverage into predefined percentage blocks, are presented

  4. Efficient Nash Equilibrium Resource Allocation Based on Game Theory Mechanism in Cloud Computing by Using Auction

    PubMed Central

    Nezarat, Amin; Dastghaibifard, GH

    2015-01-01

    One of the most complex issues in the cloud computing environment is the problem of resource allocation so that, on one hand, the cloud provider expects the most profitability and, on the other hand, users also expect to have the best resources at their disposal considering the budget constraints and time. In most previous work conducted, heuristic and evolutionary approaches have been used to solve this problem. Nevertheless, since the nature of this environment is based on economic methods, using such methods can decrease response time and reducing the complexity of the problem. In this paper, an auction-based method is proposed which determines the auction winner by applying game theory mechanism and holding a repetitive game with incomplete information in a non-cooperative environment. In this method, users calculate suitable price bid with their objective function during several round and repetitions and send it to the auctioneer; and the auctioneer chooses the winning player based the suggested utility function. In the proposed method, the end point of the game is the Nash equilibrium point where players are no longer inclined to alter their bid for that resource and the final bid also satisfies the auctioneer’s utility function. To prove the response space convexity, the Lagrange method is used and the proposed model is simulated in the cloudsim and the results are compared with previous work. At the end, it is concluded that this method converges to a response in a shorter time, provides the lowest service level agreement violations and the most utility to the provider. PMID:26431035

  5. Theoretically Founded Optimization of Auctioneer's Revenues in Expanding Auctions

    NASA Astrophysics Data System (ADS)

    Rabin, Jonathan; Shehory, Onn

    The expanding auction is a multi-unit auction which provides the auctioneer with control over the outcome of the auction by means of dynamically adding items for sale. Previous research on the expanding auction has provided a numeric method to calculate a strategy that optimizes the auctioneer's revenue. In this paper, we analyze various theoretical properties of the expanding auction, and compare it to VCG, a multi-unit auction protocol known in the art. We examine the effects of errors in the auctioneer's estimation of the buyers' maximal bidding values and prove a theoretical bound on the ratio between the revenue yielded by the Informed Decision Strategy (IDS) and the post-optimal strategy. We also analyze the relationship between the auction step and the optimal revenue and introduce a method of computing this optimizing step. We further compare the revenues yielded by the use of IDS with an expanding auction to those of the VCG mechanism and determine the conditions under which the former outperforms the latter. Our work provides new insight into the properties of the expanding auction. It further provides theoretically founded means for optimizing the revenue of auctioneer.

  6. Reputation mechanism: From resolution for truthful online auctions to the model of optimal one-gambler problem

    SciTech Connect

    Bradonjic, Milan

    2009-01-01

    In this paper we study reputation mechanisms, and show how the notion of reputation can help us in building truthful online auction mechanisms. From the mechanism design prospective, we derive the conditions on and design a truthful online auction mechanism. Moreover, in the case when some agents may lay or cannot have the real knowledge about the other agents reputations, we derive the resolution of the auction, such that the mechanism is truthful. Consequently, we move forward to the optimal one-gambler/one-seller problem, and explain how that problem is refinement of the previously discussed online auction design in the presence of reputation mechanism. In the setting of the optimal one-gambler problem, we naturally rise and solve the specific question: What is an agent's optimal strategy, in order to maximize his revenue? We would like to stress that our analysis goes beyond the scope, which game theory usually discusses under the notion of reputation. We model one-player games, by introducing a new parameter (reputation), which helps us in predicting the agent's behavior, in real-world situations, such as, behavior of a gambler, real-estate dealer, etc.

  7. Three essays on auction markets

    NASA Astrophysics Data System (ADS)

    Shunda, Nicholas James

    This dissertation contains a series of theoretical investigations of auction markets. The essays it contains cover wholesale electricity markets, a popular selling mechanism on eBay, and supplier entry into multi-unit procurement auctions. The study in Chapter 1 compares the procurement cost-minimizing and productive efficiency performance of the auction mechanism used by independent system operators in wholesale electricity auction markets in the U.S. with that of a proposed alternative. The current practice allocates energy contracts as if the auction featured a discriminatory final payment method when, in fact, the markets are uniform price auctions. The proposed alternative explicitly accounts for the market-clearing price during the allocation phase. We find that the proposed alternative largely outperforms the current practice on the basis of procurement costs in the context of simple auction markets featuring both day-ahead and real-time auctions and that the procurement cost advantage of the alternative is complete when we simulate the effects of increased competition. We also find that a tradeoff between the objectives of procurement cost minimization and productive efficiency emerges in our simple auction markets and persists in the face of increased competition. The study in Chapter 2 considers a possible rationale for an auction with a buy price. In an auction with a buy price, the seller provides bidders with an option to end the auction early by accepting a transaction at a posted price. The "Buy-It-Now" option on eBay is a leading example of an auction with a buy price. The study develops a model of an auction with a buy price in which bidders use the auction's reserve price and buy price to formulate a reference price. The model both explains why a revenue-maximizing seller would want to augment her auction with a buy price and demonstrates that the seller sets a higher reserve price when she can affect the bidders' reference price through the

  8. Auctioning Airport Slots?

    NASA Technical Reports Server (NTRS)

    Gruyer, Nicolas; Lenoir, Nathalie

    2003-01-01

    The current allocation of slots on congested European airports constitutes an obstacle to the effective liberalisation of air transportation undertaken in Europe. With a view to favouring effluent slot utilisation and competition, as is the goal of the Euopean commission, we propose to use a market mechanism, based on temporary" utilisation licences. In order to allocate those licences, we propose and describe an iterated combinatorial auction mechanism where a percentage of licences would be reallocated each season. A secondary market would also be set up in order to reallocate slots during a season. Since a combinatorial auction involve a complex optimisation procedure, we describe how it can be made to work in the case of auctions.

  9. Auction-based bandwidth allocation in the Internet

    NASA Astrophysics Data System (ADS)

    Wei, Jiaolong; Zhang, Chi

    2002-07-01

    It has been widely accepted that auctioning which is the pricing approach with minimal information requirement is a proper tool to manage scare network resources. Previous works focus on Vickrey auction which is incentive compatible in classic auction theory. In the beginning of this paper, the faults of the most representative auction-based mechanisms are discussed. And then a new method called uniform-price auction (UPA), which has the simplest auction rule is proposed and it's incentive compatibility in the network environment is also proved. Finally, the basic mode is extended to support applications which require minimum bandwidth guarantees for a given time period by introducing derivative market, and a market mechanism for network resource allocation which is predictable, riskless, and simple for end-users is completed.

  10. Auction-based Security Game for Multiuser Cooperative Networks

    NASA Astrophysics Data System (ADS)

    Wang, An; Cai, Yueming; Yang, Wendong; Cheng, Yunpeng

    2013-04-01

    In this paper, we develop an auction-based algorithm to allocate the relay power efficiently to improve the system secrecy rate in a cooperative network, where several source-destination pairs and one cooperative relay are involved. On the one hand, the cooperative relay assists these pairs to transmit under a peak power constraint. On the other hand, the relay is untrusty and is also a passive eavesdropper. The whole auction process is completely distributed and no instantaneous channel state information exchange is needed. We also prove the existence and uniqueness of the Nash Equilibrium (NE) for the proposed power auction game. Moreover, the Pareto optimality is also validated. Simulation results show that our proposed auction-based algorithm can effectively improve the system secrecy rate. Besides, the proposed auction-based algorithm can converge to the unique NE point within a finite number of iterations. More interestingly, we also find that the proposed power auction mechanism is cheat-proof.

  11. Earthquakes with non--double-couple mechanisms.

    PubMed

    Frohlich, C

    1994-05-01

    Seismological observations confirm that the pattern of seismic waves from some earthquakes cannot be produced by slip along a planar fault surface. More than one physical mechanism is required to explain the observed varieties of these non-double-couple earthquakes. The simplest explanation is that some earthquakes are complex, with stress released on two or more suitably oriented, nonparallel fault surfaces. However, some shallow earthquakes in volcanic and geothermal areas require other explanations. Current research focuses on whether fault complexity explains most observed non-double-couple earthquakes and to what extent ordinary earthquakes have non-double-couple components.

  12. Essays on wholesale auctions in deregulated electricity markets

    NASA Astrophysics Data System (ADS)

    Baltaduonis, Rimvydas

    2007-12-01

    The early experience in the restructured electric power markets raised several issues, including price spikes, inefficiency, security, and the overall relationship of market clearing prices to generation costs. Unsatisfactory outcomes in these markets are thought to have resulted in part from strategic generator behaviors encouraged by inappropriate market design features. In this dissertation, I examine the performance of three auction mechanisms for wholesale power markets - Offer Cost Minimization auction, Payment Cost Minimization auction and Simple-Offer auction - when electricity suppliers act strategically. A Payment Cost Minimization auction has been proposed as an alternative to the traditional Offer Cost Minimization auction with the intention to solve the problem of inflated wholesale electricity prices. Efficiency concerns for this proposal were voiced due to insights predicated on the assumption of true production cost revelation. Using a game theoretic approach and an experimental method, I compare the two auctions, strictly controlling for the level of unilateral market power. A specific feature of these complex-offer auctions is that the sellers submit not only the quantities and the minimum prices that they are willing to sell at, but also the start-up fees, which are designed to reimburse the fixed start-up costs of the generation plants. I find that the complex structure of the offers leaves considerable room for strategic behavior, which consequently leads to anti-competitive and inefficient market outcomes. In the last chapter of my dissertation, I use laboratory experiments to contrast the performance of two complex-offer auctions against the performance of a simple-offer auction, in which the sellers have to recover all their generation costs - fixed and variable - through a uniform market-clearing price. I find that a simple-offer auction significantly reduces consumer prices and lowers price volatility. It mitigates anti-competitive effects

  13. Double Froggatt-Nielsen mechanism

    NASA Astrophysics Data System (ADS)

    Nishiwaki, Kenji; Shimizu, Yusuke; Tatsuta, Yoshiyuki

    2016-08-01

    We present a doubly parametric extension of the standard Froggatt-Nielsen (FN) mechanism. As is well known, mass matrices of the up- and down-type quark sectors and the charged lepton sector in the standard model can be parametrized well by a parameter λ which is usually taken to be the sine of the Cabibbo angle (λ=sinθ≃0.225). However, in the neutrino sector, there is still room to realize the two neutrino mass squared differences Δmsol2 and Δmatm2, two large mixing angles θ and θ, and non-zero θ. Then we consider an extension with an additional parameter ρ in addition to λ. Taking the relevant FN charges for a power of λ(=0.225) and additional FN charges for a power of ρ, which we assume to be less than one, we can reproduce the ratio of the two neutrino mass squared differences and three mixing angles. In the normal neutrino mass hierarchy, we show several patterns for taking relevant FN charges and the magnitude of ρ. We find that if sinθ is measured more precisely, we can distinguish each pattern. This is testable in the near future, for example in neutrino oscillation experiments. In addition, we predict the Dirac CP-violating phase for each pattern.

  14. Mechanical response of biopolymer double networks

    NASA Astrophysics Data System (ADS)

    Carroll, Joshua; Das, Moumita

    We investigate a double network model of articular cartilage (AC) and characterize its equilibrium mechanical response. AC has very few cells and the extracellular matrix mainly determines its mechanical response. This matrix can be thought of as a double polymer network made of collagen and aggrecan. The collagen fibers are stiff and resist tension and compression forces, while aggrecans are flexible and control swelling and hydration. We construct a microscopic model made of two interconnected disordered polymer networks, with fiber elasticity chosen to qualitatively mimic the experimental system. We study the collective mechanical response of this double network as a function of the concentration and stiffness of the individual components as well as the strength of the connection between them using rigidity percolation theory. Our results may provide a better understanding of mechanisms underlying the mechanical resilience of AC, and more broadly may also lead to new perspectives on the mechanical response of multicomponent soft materials. This work was partially supported by a Cottrell College Science Award.

  15. A novel mechanism for creating double pulsars

    NASA Technical Reports Server (NTRS)

    Sigurdsson, Steinn; Hernquist, Lars

    1992-01-01

    Simulations of encounters between pairs of hard binaries, each containing a neutron star and a main-sequence star, reveal a new formation mechanism for double pulsars in dense cores of globular clusters. In many cases, the two normal stars are disrupted to form a common envelope around the pair of neutron stars, both of which will be spun up to become millisecond pulsars. We predict that a new class of pulsars, double millisecond pulsars, will be discovered in the cores of dense globular clusters. The genesis proceeds through a short-lived double-core common envelope phase, with the envelope ejected in a fast wind. It is possible that the progenitor may also undergo a double X-ray binary phase. Any circular, short-period double pulsar found in the galaxy would necessarily come from disrupted disk clusters, unlike Hulse-Taylor class pulsars or low-mass X-ray binaries which may be ejected from clusters or formed in the galaxy.

  16. Lessons from the Electricity Auctions in Brazil

    SciTech Connect

    Dutra, Joisa; Menezes, Flavio

    2005-12-01

    The first lesson to emerge from the recent auctions falls within a category that might be described as 'higher costs of reforms in developing economies.' These range from bidders' fears of future government-imposed price caps to technical issues, such as the potential loss of efficiency resulting from bidders' lack of knowledge about ceiling prices, reference supply, and the demand reduction mechanism.

  17. A Study of Central Auction Based Wholesale Electricity Markets

    NASA Astrophysics Data System (ADS)

    Ceppi, Sofia; Gatti, Nicola

    The deregulation of electricity markets produced significant economic benefits, reducing prices to customers and opening several opportunities for new actors, e.g., new generators and distributors. A prominent scientific and technological challenge is the automation of such markets. In particular, we focus our attention on wholesale electricity markets based on a central auction. In these markets, generators sell electricity by means of a central auction to a public authority. Instead, the distribution of electricity to customers takes part in retail markets. The main works presented in the literature model wholesale markets as oligopolies, neglecting thus the specific auction mechanism. In this paper, we enrich these models by introducing an auction mechanism shaped on that used in the Italian wholesale electricity market, we solve the winner determination problem, and we preliminarily study the problem of searching for equilibria.

  18. The Double Cone: A Mechanical Paradox or a Geometrical Constraint?

    ERIC Educational Resources Information Center

    Gallitto, Aurelio Agliolo; Fiordilino, Emilio

    2011-01-01

    In the framework of the Italian National Plan "Lauree Scientifiche" (PLS) in collaboration with secondary schools, we have investigated the mechanical paradox of the double cone. We have calculated the geometric condition for obtaining an upward movement. Based on this result, we have built a mechanical model with a double cone made of aluminum…

  19. Multiunit auctions with complementarities: Issues of efficiency in electricity auctions

    NASA Astrophysics Data System (ADS)

    Elmaghraby, Wedad Jasmine

    Many governments are beginning to believe that it is in their and their constituents' best interest to deregulate their electricity supply industries (ESI). Electricity supply industries in the United Kingdom, Australia, Chile, Norway and the United States have been, or are currently being, restructured. Amongst the many challenges facing the deregulated ESI is to create an auction that induces an efficient use of generation resources, i.e., the efficient dispatch. The design of an electricity auction that induces an efficient use of generation resources is complicated by the fact that electricity demand, which fluctuates from hour to hour, must be satisfied by different generation technologies with nonconvex costs, and that, with the exception of hydro resources, the generators lack the ability to store electricity in inventory. In this dissertation, I analyze the performance of different auction structures in minimizing generation costs. In particular, I am interested in identifying which, if any, rules in an auction structure are necessary and sufficient to guarantee productive minimization of generation costs, in equilibrium. I conduct my analysis assuming two informational frameworks their own costs and all of their opponents' costs with certainty (Chapter 2), and each generator knows its own costs but is uncertain as to what its opponents' costs may be (Chapter 3). The results of chapters 2 and 3 support each other and indicate that the current auction structures operating in California, the UK and Australia are not able to guarantee productive efficiency. Instead, an auction design that takes into account the structure of generation costs has superior (theoretical) efficiency properties. By auctioning daily electricity demand according to its duration, while limiting the size of the demand bundle to be no greater than the capacity of a generation plant, generators are able to bid so as to reflect their cost advantages. This auction format, labeled an alpha

  20. Mechanical seal having a double-tier mating ring

    DOEpatents

    Khonsari, Michael M.; Somanchi, Anoop K.

    2005-09-13

    An apparatus and method to enhance the overall performance of mechanical seals in one of the following ways: by reducing seal face wear, by reducing the contact surface temperature, or by increasing the life span of mechanical seals. The apparatus is a mechanical seal (e.g., single mechanical seals, double mechanical seals, tandem mechanical seals, bellows, pusher mechanical seals, and all types of rotating and reciprocating machines) comprising a rotating ring and a double-tier mating ring. In a preferred embodiment, the double-tier mating ring comprises a first and a second stationary ring that together form an agitation-inducing, guided flow channel to allow for the removal of heat generated at the seal face of the mating ring by channeling a coolant entering the mating ring to a position adjacent to and in close proximity with the interior surface area of the seal face of the mating ring.

  1. Mechanically tough, elastic and stable rope-like double nanohelices

    NASA Astrophysics Data System (ADS)

    Dai, L.; Huang, X. J.; Dong, L. X.; Zhang, Q.; Zhang, L.

    2014-07-01

    Double helix nanostructures have been the object of intense theoretical and experimental investigations in recent years due to their various types of available materials and unique morphology. Among these structures, rope-like double nanohelices of two strands in contact along a line can be obtained using any one-dimensional nanostructure. In this work, we establish a novel theory for quantitatively exploring the statics and dynamics of rope-like double nanohelices by employing the concept of the extensible Cosserat curve. The rope-like double nanohelices are tough, relatively elastic, and mechanically stable, which agrees well with the experiments. The characteristics of the interaction between the two strands, the tensile modulus and the torque are precisely described and explained across the entire stretching region. The proposed model offers in depth quantitative insight into the mechanics of double helix nanostructures, and supplies a reliable reference for further experimental research.

  2. Internet Auction Sellers: Does Size Really Matter?

    ERIC Educational Resources Information Center

    Halstead, Diane; Becherer, Richard C.

    2003-01-01

    Examines the Internet auction phenomenon as it relates to the marketing mix of online auction sellers. The data indicate that, while there is great diversity among businesses that utilize online auctions, distinct cost leadership and differentiation marketing strategies are both evident. These two approaches are further distinguished in terms of…

  3. Exploring Online Auction Behaviors and Motivations

    ERIC Educational Resources Information Center

    Jeon, Sua; Crutsinger, Christy; Kim, Haejung

    2008-01-01

    The availability and convenience of the Internet, combined with the variety of products available at any given time, have contributed to the success of online auctions.This exploratory study examined online auction behaviors among college students in an attempt to identify underlying dimensions of auction motivations. Questionnaires completed by…

  4. 7 CFR 1955.148 - Auction sales.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false Auction sales. 1955.148 Section 1955.148 Agriculture... REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.148 Auction sales. This section provides guidance on the sale of all inventory property by auction, except FSA...

  5. 7 CFR 1955.148 - Auction sales.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true Auction sales. 1955.148 Section 1955.148 Agriculture... REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.148 Auction sales. This section provides guidance on the sale of all inventory property by auction, except FSA...

  6. 7 CFR 1955.148 - Auction sales.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 14 2014-01-01 2014-01-01 false Auction sales. 1955.148 Section 1955.148 Agriculture... REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.148 Auction sales. This section provides guidance on the sale of all inventory property by auction, except FSA...

  7. 7 CFR 1955.148 - Auction sales.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 14 2013-01-01 2013-01-01 false Auction sales. 1955.148 Section 1955.148 Agriculture... REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.148 Auction sales. This section provides guidance on the sale of all inventory property by auction, except FSA...

  8. 7 CFR 1955.148 - Auction sales.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 14 2012-01-01 2012-01-01 false Auction sales. 1955.148 Section 1955.148 Agriculture... REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.148 Auction sales. This section provides guidance on the sale of all inventory property by auction, except FSA...

  9. 7 CFR 46.25 - Auction sales.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Auction sales. 46.25 Section 46.25 Agriculture... THAN RULES OF PRACTICE) UNDER THE PERISHABLE AGRICULTURAL COMMODITIES ACT, 1930 Auction Sales § 46.25 Auction sales. Commission merchants, dealers and brokers who offer produce for sale through...

  10. 7 CFR 46.25 - Auction sales.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Auction sales. 46.25 Section 46.25 Agriculture... THAN RULES OF PRACTICE) UNDER THE PERISHABLE AGRICULTURAL COMMODITIES ACT, 1930 Auction Sales § 46.25 Auction sales. Commission merchants, dealers and brokers who offer produce for sale through...

  11. Truthful Auction for CPU Time Slots

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Li, Minming

    We consider the task of designing a truthful auction mechanism for CPU time scheduling problem. There are m commodities (time slots) T = {t 1, t 2, ...,t m } for n buyers I = {1,2,...,n}. Each buyer requires a number of time slots s i for its task. The valuation function of buyer i for a bundle of time slots T i is v i (T i ) = w i (m - t), where t is the last time slot in T i and |T i | = s i . The utility u i of buyer i is v i (T i ) - p(T i ). It is well-known that Vickrey-Clarke-Groves (VCG) mechanism gives the incentive to bid truthfully. Although optimal social welfare is computationally feasible in CPU time scheduling problem, VCG mechanism may produce low revenue. We design an auction which also maintains the incentives for bidders to bid truthfully. In addition, we perform simulations and observe that our truthful mechanism produces more revenue than VCG on average.

  12. Statistical Properties of Online Auctions

    NASA Astrophysics Data System (ADS)

    Namazi, Alireza; Schadschneider, Andreas

    We characterize the statistical properties of a large number of online auctions run on eBay. Both stationary and dynamic properties, like distributions of prices, number of bids etc., as well as relations between these quantities are studied. The analysis of the data reveals surprisingly simple distributions and relations, typically of power-law form. Based on these findings we introduce a simple method to identify suspicious auctions that could be influenced by a form of fraud known as shill bidding. Furthermore the influence of bidding strategies is discussed. The results indicate that the observed behavior is related to a mixture of agents using a variety of strategies.

  13. Toughening Mechanism of Double Network Hydrogels

    NASA Astrophysics Data System (ADS)

    Gong, Jian Ping

    2010-03-01

    The fundamental toughening mechanism of DN gels [1] is of great interest to researchers. Extensive experimental and theoretical studies have been performed to explain this mechanism [2-7]. Yielding and necking deformation [2] that was observed through tensile tests and rate-independent hysteresis [3] observed through cyclic loading tests have indicated that DN gels can accumulate internal damage before the suffering macroscopic fracture; after damage accumulation, the DN gels become much softer. We assume that on the microscopic level, yielding is caused by the partial breakage and fragmentation of the brittle first network and interconnection among the fragments by the polymer chains of second network [2]. Brown [4] and Tanaka [5] have proposed similar models that can qualitatively explain the anomalously high fracture energy, assuming that the DN gel is locally damaged (yielded) around the crack tip and that the energy dissipated for damage accumulation enhances the effective fracture energy. Using AFM measurements [6] and 3D color laser microscope[7], we successfully detected the existence of softened regions, of several hundreds μm in thickness, at the crack tip just below the fracture surfaces, which supports the assumption of localized damage accumulation. A linear relationship between the thickness of the softened yielding zone and the fracture energy of the gel was observed, which is in agreement with the local yielding zone explanation. [4pt] [1] Gong, J. P.; Katsuyama, Y.; Kurokawa, T.; Osada, Y. Adv. Mater. 2003, 15, 1155. [0pt] [2] Na Y.H., Tanaka Y., Kawauchi Y., Furukawa H., Sumiyoshi T., Gong J. P., Osada Y., Macromolecules 2006, 39(14), 4641. [0pt] [3] Webber, R. E.; Creton, C.; Brown, H. R.; Gong, J. P. Macromolecules 2007, 40, 2919. [0pt] [4] Brown, H. R. Macromolecules 2007, 40, 3815. [0pt] [5] Tanaka, Y. Euro Phys. Letter. 2007, 78, 56005. [0pt] [6] Tanaka Y.; Kawauchi Y.; Kurokawa T.; Furukawa H.; Okajima T.; Gong J. P. Macrom. Rapid Comm

  14. Biological auctions with multiple rewards.

    PubMed

    Reiter, Johannes G; Kanodia, Ayush; Gupta, Raghav; Nowak, Martin A; Chatterjee, Krishnendu

    2015-08-01

    The competition for resources among cells, individuals or species is a fundamental characteristic of evolution. Biological all-pay auctions have been used to model situations where multiple individuals compete for a single resource. However, in many situations multiple resources with various values exist and single reward auctions are not applicable. We generalize the model to multiple rewards and study the evolution of strategies. In biological all-pay auctions the bid of an individual corresponds to its strategy and is equivalent to its payment in the auction. The decreasingly ordered rewards are distributed according to the decreasingly ordered bids of the participating individuals. The reproductive success of an individual is proportional to its fitness given by the sum of the rewards won minus its payments. Hence, successful bidding strategies spread in the population. We find that the results for the multiple reward case are very different from the single reward case. While the mixed strategy equilibrium in the single reward case with more than two players consists of mostly low-bidding individuals, we show that the equilibrium can convert to many high-bidding individuals and a few low-bidding individuals in the multiple reward case. Some reward values lead to a specialization among the individuals where one subpopulation competes for the rewards and the other subpopulation largely avoids costly competitions. Whether the mixed strategy equilibrium is an evolutionarily stable strategy (ESS) depends on the specific values of the rewards. PMID:26180069

  15. Biological auctions with multiple rewards.

    PubMed

    Reiter, Johannes G; Kanodia, Ayush; Gupta, Raghav; Nowak, Martin A; Chatterjee, Krishnendu

    2015-08-01

    The competition for resources among cells, individuals or species is a fundamental characteristic of evolution. Biological all-pay auctions have been used to model situations where multiple individuals compete for a single resource. However, in many situations multiple resources with various values exist and single reward auctions are not applicable. We generalize the model to multiple rewards and study the evolution of strategies. In biological all-pay auctions the bid of an individual corresponds to its strategy and is equivalent to its payment in the auction. The decreasingly ordered rewards are distributed according to the decreasingly ordered bids of the participating individuals. The reproductive success of an individual is proportional to its fitness given by the sum of the rewards won minus its payments. Hence, successful bidding strategies spread in the population. We find that the results for the multiple reward case are very different from the single reward case. While the mixed strategy equilibrium in the single reward case with more than two players consists of mostly low-bidding individuals, we show that the equilibrium can convert to many high-bidding individuals and a few low-bidding individuals in the multiple reward case. Some reward values lead to a specialization among the individuals where one subpopulation competes for the rewards and the other subpopulation largely avoids costly competitions. Whether the mixed strategy equilibrium is an evolutionarily stable strategy (ESS) depends on the specific values of the rewards.

  16. Multiparty quantum sealed-bid auction using single photons as message carrier

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Jie; Wang, Hai-Bin; Yuan, Gong-Lin; Xu, Yong; Chen, Zhen-Yu; An, Xing-Xing; Ji, Fu-Gao; Gnitou, Gnim Tchalim

    2016-02-01

    In this study, a novel multiparty quantum sealed-bid auction protocol using the single photons as the message carrier of bids is proposed, followed by an example of three-party auction. Compared with those protocols based on the entangled states (GHZ state, EPR pairs, etc.), the present protocol is more economic and feasible within present technology. In order to guarantee the security and the fairness of the auction, the decoy photon checking technique and an improved post-confirmation mechanism with EPR pairs are introduced, respectively.

  17. Auctions with Dynamic Populations: Efficiency and Revenue Maximization

    NASA Astrophysics Data System (ADS)

    Said, Maher

    We study a stochastic sequential allocation problem with a dynamic population of privately-informed buyers. We characterize the set of efficient allocation rules and show that a dynamic VCG mechanism is both efficient and periodic ex post incentive compatible; we also show that the revenue-maximizing direct mechanism is a pivot mechanism with a reserve price. We then consider sequential ascending auctions in this setting, both with and without a reserve price. We construct equilibrium bidding strategies in this indirect mechanism where bidders reveal their private information in every period, yielding the same outcomes as the direct mechanisms. Thus, the sequential ascending auction is a natural institution for achieving either efficient or optimal outcomes.

  18. Auctions for coastal energy resources

    NASA Astrophysics Data System (ADS)

    Griffin, Robert M.

    It is becoming increasingly common to allocate public resources to the private sector for the purpose of developing these resources. One of the earliest uses of auctions in the U.S. for allocating rights to public resources was in the offshore oil and gas industry. The U.S. Federal government, through the Department of Interior (DOI), has used auctions to allocate development rights to offshore oil and gas resources to the private sector since the 1950's. Since then many things have changed. Oil and gas markets have gone through boom and bust cycles, giant technological advances in extraction and assessment have taken place, and alternative energy based in the coastal zone is now in demand in markets as well. There has been an enormous amount of research into the drivers of bidder behavior in auctions and optimal auction design in the last 60 years as well. Throughout all of this, the DOI has continued to use basically the same exact auction design to allocate oil and gas leases. The U.S. offshore oil and gas resources sold by the Department of Interior have accounted for more than $65 billion in revenue since the program started. These offshore resources are an important source of government revenue and national wealth. Additionally, the expansion of the energy sector offshore has enormous potential for electricity generation in the U.S., estimated by the National Renewable Energy Laboratory as approaching 54 gigawatts by 2030 (U.S. Department of Energy, 2008). Taken together, the DOI controls access to a large part of the future of energy in the U.S. The research herein assesses the auction formats used to allocate both fossil fuels and renewable resources on the Outer Continental Shelf (OCS). The first manuscript looks at the current method used by the DOI to allocate oil and gas leases on the OCS, and is primarily interested in how bidders behave in this environment. Using latent class estimation techniques to separate distinct bidding behavior in a laboratory

  19. New mechanisms for double charmed meson production at the LHCb

    NASA Astrophysics Data System (ADS)

    Maciuła, Rafał; Saleev, Vladimir A.; Shipilova, Alexandra V.; Szczurek, Antoni

    2016-07-01

    We discuss production of D0D0 (and Dbar0Dbar0) pairs related to the LHCb Collaboration results for √{ s} = 7 TeV in proton-proton scattering. We consider double-parton scattering (DPS) mechanisms of double c c bar production and subsequent cc →D0D0 hadronization as well as double g and mixed gc c bar production with gg →D0D0 and gc →D0D0 hadronization calculated with the help of the scale-dependent hadronization functions of Kniehl et al. Single-parton scattering (SPS) mechanism of digluon production is also taken into account. We compare our results with several correlation observables in azimuthal angle φD0D0 between D0 mesons or in dimeson invariant mass MD0D0. The inclusion of new mechanisms with g →D0 fragmentation leads to larger cross sections, than when including only DPS mechanism cc →D0D0 with standard scale-independent fragmentation functions. Some consequences of the presence of the new mechanisms are discussed. In particular a larger σeff is needed to describe the LHCb data. There is a signature that σeff may depend on transverse momentum of c quarks and/or c bar antiquarks.

  20. Orientation and mechanical response of elastomers containing double networks

    SciTech Connect

    Roland, C.M.; Santangelo, P.G.; Choi, I.S.; Miller J.B.

    1993-12-31

    Orientation is one of the primary means for increasing the modulus and strength of materials comprised of flexible chain polymers. The incorporation of a double network makes the orientation of a flexible chain polymer thermodynamically stable, thus offering the potential for elastomers with improved physical properties. Birefringence and deuterium NMR results will be presented which indicate that the high residual strains obtained via double network formation are accompanied by surprisingly low levels of molecular orientation. It has been found that the presence of a double network amplifies the modulus, strain crystallizability, and, in conjunction with carbon black reinforcement, the electrical conductivity of rubber. Most intriguing is the fact that the modulus increase may not associate with any increased brittleness, as would result from simply increasing the crosslink density. Mechanisms for the modulus enhancement will be proposed and examined.

  1. 76 FR 81932 - Auction of FM Broadcast Construction Permits; Revised Construction Permit Number in Auction 93

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... COMMISSION Auction of FM Broadcast Construction Permits; Revised Construction Permit Number in Auction 93... the construction permit number for one of the FM broadcast construction permits for Auction 93. FOR...'s Electronic Comment Filing System (ECFS) Web page at http://www.fcc.gov/cgb/ecfs/ . ] 1....

  2. 40 CFR 73.73 - Delegation of auctions and sales and termination of auctions and sales.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Delegation of auctions and sales and termination of auctions and sales. 73.73 Section 73.73 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE ALLOWANCE SYSTEM Auctions, Direct Sales,...

  3. 40 CFR 73.73 - Delegation of auctions and sales and termination of auctions and sales.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Delegation of auctions and sales and termination of auctions and sales. 73.73 Section 73.73 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE ALLOWANCE SYSTEM Auctions, Direct Sales,...

  4. 40 CFR 73.73 - Delegation of auctions and sales and termination of auctions and sales.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Delegation of auctions and sales and termination of auctions and sales. 73.73 Section 73.73 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE ALLOWANCE SYSTEM Auctions, Direct Sales,...

  5. 40 CFR 73.73 - Delegation of auctions and sales and termination of auctions and sales.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Delegation of auctions and sales and termination of auctions and sales. 73.73 Section 73.73 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE ALLOWANCE SYSTEM Auctions, Direct Sales,...

  6. 40 CFR 73.73 - Delegation of auctions and sales and termination of auctions and sales.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Delegation of auctions and sales and termination of auctions and sales. 73.73 Section 73.73 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE ALLOWANCE SYSTEM Auctions, Direct Sales,...

  7. Electrical power generation by mechanically modulating electrical double layers.

    PubMed

    Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

    2013-01-01

    Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future. PMID:23403587

  8. Electrical power generation by mechanically modulating electrical double layers.

    PubMed

    Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

    2013-01-01

    Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future.

  9. Immune Mechanism: A ‘Double-Edged Sword’

    PubMed Central

    Musa, Mustaffa

    2013-01-01

    Immunology has now developed into an independent discipline in medicine which covers not only germ infection which is related to immunity solely but also covers a lot of non-infectious diseases such as autoimmune disease, allergies, and others. Therefore, “The Immune Mechanism: “A Double-Edged Sword” means that the immune mechanism (consisted of antibody mediated mechanism and T cell mediated mechanism), just like one edge playing the role of giving benefit (immunity) as it destroys the agent of infection, and another one can be detrimental as it will cause tissue/cell damages and then give rise to immune diseases (immunopathology). Now, the prevalence of these immune diseases is on the rise and has become a new challenge to our country towards developed country in 2020. Therefore, we have to make ample preparation (laboratory facilities/services, main power, and research) from now on in order to face the problems and challenges. PMID:23966827

  10. 7 CFR 29.36 - Auction market.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Auction market. 29.36 Section 29.36 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Definitions § 29.36 Auction market. A place to which tobacco is delivered by...

  11. 7 CFR 29.36 - Auction market.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Auction market. 29.36 Section 29.36 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Regulations Definitions § 29.36 Auction market. A place to which tobacco is delivered by...

  12. Electrical Power Generation by Mechanically Modulating Electrical Double Layers

    NASA Astrophysics Data System (ADS)

    Lee, Dongyun; Moon, Jong Kyun; Jeong, Jaeki; Pak, Hyuk Kyu

    2012-11-01

    Many objects in contact with a liquid acquire some electronic charges on their surfaces. These charges on the surface attract counter ions from the liquid phase. This complex system is called electrical double layer (EDL). Since its geometry and structure is similar to an electric capacitor, it is also called an electrical double layer capacitor (EDLC). In this work we studied two EDLCs formed in a liquid droplet bridge between two parallel solid conducting plates. We found that when the bridge height was mechanically modulated, each EDLC was continuously charged and discharged generating an AC electric current across the plates. The results of this experiment can be useful for constructing a micro-fluidic power generation.

  13. Collusion in Auctions for Emission Permits: An Experimental Analysis

    ERIC Educational Resources Information Center

    Burtraw, Dallas; Goeree, Jacob; Holt, Charles A.; Myers, Erica; Palmer, Karen; Shobe, William

    2009-01-01

    Environmental markets have several institutional features that provide a new context for the use of auctions and that have not been studied previously. This paper reports on laboratory experiments testing three auction forms--uniform and discriminatory price sealed-bid auctions and an ascending clock auction. We test the ability of subjects to…

  14. Auction-based resource allocation game under a hierarchical structure

    NASA Astrophysics Data System (ADS)

    Cui, Yingying; Zou, Suli; Ma, Zhongjing

    2016-01-01

    This paper studies a class of auction-based resource allocation games under a hierarchical structure, such that each supplier is assigned a certain amount of resource from a single provider and allocates it to its buyers with auction mechanisms. To implement the efficient allocations for the underlying hierarchical system, we first design an auction mechanism, for each local system composed of a supplier and its buyers, which inherits the advantages of the progressive second price mechanism. By employing a dynamic algorithm, each local system converges to its own efficient Nash equilibrium, at which the efficient resource allocation is achieved and the bidding prices of all the buyers in this local system are identical with each other. After the local systems reach their own equilibria respectively, the resources assigned to suppliers are readjusted via a dynamic hierarchical algorithm with respect to the bidding prices associated with the implemented equilibria of local systems. By applying the proposed hierarchical process, the formulated hierarchical system can converge to the efficient allocation under certain mild conditions. The developed results in this work are demonstrated with simulations.

  15. The beginning of a seed: regulatory mechanisms of double fertilization

    PubMed Central

    Bleckmann, Andrea; Alter, Svenja; Dresselhaus, Thomas

    2014-01-01

    The launch of seed development in flowering plants (angiosperms) is initiated by the process of double fertilization: two male gametes (sperm cells) fuse with two female gametes (egg and central cell) to form the precursor cells of the two major seed components, the embryo and endosperm, respectively. The immobile sperm cells are delivered by the pollen tube toward the ovule harboring the female gametophyte by species-specific pollen tube guidance and attraction mechanisms. After pollen tube burst inside the female gametophyte, the two sperm cells fuse with the egg and central cell initiating seed development. The fertilized central cell forms the endosperm while the fertilized egg cell, the zygote, will form the actual embryo and suspensor. The latter structure connects the embryo with the sporophytic maternal tissues of the developing seed. The underlying mechanisms of double fertilization are tightly regulated to ensure delivery of functional sperm cells and the formation of both, a functional zygote and endosperm. In this review we will discuss the current state of knowledge about the processes of directed pollen tube growth and its communication with the synergid cells resulting in pollen tube burst, the interaction of the four gametes leading to cell fusion and finally discuss mechanisms how flowering plants prevent multiple sperm cell entry (polyspermy) to maximize their reproductive success. PMID:25309552

  16. 78 FR 61350 - Tribal Mobility Fund Phase I Auction (Auction 902); Short-Form Application Filing Window...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-03

    .... In the list of bidding areas released with the Auction 902 Procedures Public Notice, 78 FR 56875... COMMISSION Tribal Mobility Fund Phase I Auction (Auction 902); Short-Form Application Filing Window... Bureau, Auctions and Spectrum Access Division: For Tribal Mobility Fund Phase I questions:...

  17. Double-exchange mechanism in rare-earth compounds

    SciTech Connect

    Gulacsi, M.

    2015-03-15

    We show that double-exchange mechanism is responsible for ferromagnetism in low dimensional rare-earth compounds. We use the bosonized version of the one-dimensional Anderson lattice model in Toulouse limit to characterize the properties of the emerging ferromagnetic phase. We give a comprehensive description of the ferromagnetic ordering of the correlated electrons which appears at intermediate couplings and doping. The obtained ferromagnetic phase transitions have been identified to be an order–disorder transition of the quantum random transverse-field Ising type.

  18. Sequential Auctions in Uncertain Information Settings

    NASA Astrophysics Data System (ADS)

    Fatima, Shaheen; Wooldridge, Michael; Jennings, Nicholas R.

    This paper analyzes sequential auctions for private value objects using second-price sealed-bid rules. Now, the equilibrium bids for such auctions depend on the information uncertainty of the bidders. Specifically, there are three key auction parameters that the bidders could be uncertain about: the valuations of the objects for sale, the number of objects for sale, and the number of participating bidders. We analyse the bidding behaviour for each of these three sources of uncertainty. For each setting, we first find the equilibrium bidding strategies for the individual auctions that comprise a series. Then we analyze the effect of these uncertainties on the computational and economic properties of the equilibrium solution. The former analysis is essential if we want to use software agents to bid on our behalf. The latter is essential because both the auctioneer and the bidders want to know how these uncertainties affect their profits. Thus we compare the outcomes for these settings from the perspective of the bidders (i.e., in terms of their profits), from the perspective of the auctioneer (i.e., in terms of his revenue), and from a global perspective (i.e., in terms of auction efficiency).

  19. Electrical Power Generation by Mechanically Modulating Electrical Double Layers

    NASA Astrophysics Data System (ADS)

    Pak, Hyuk Kyu; Moon, Jong Kyun

    2014-11-01

    Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system and for understanding the interfacial charge distribution in solid-liquid interfaces in the near future. This work was supported by Center for Soft and Living Matter through IBS prgram in Korea.

  20. Quantum auctions: Facts and myths

    NASA Astrophysics Data System (ADS)

    Piotrowski, Edward W.; Sładkowski, Jan

    2008-06-01

    Quantum game theory, whatever opinions may be held due to its abstract physical formalism, have already found various applications even outside the orthodox physics domain. In this paper we introduce the concept of a quantum auction, its advantages and drawbacks. Then we describe the models that have already been put forward. A general model involves Wigner formalism and infinite dimensional Hilbert spaces - we envisage that the implementation might not be an easy task. But a restricted model advocated by the Hewlett-Packard group (Hogg et al.) seems to be much easier to implement. We focus on problems related to combinatorial auctions and technical assumptions that are made. Powerful quantum algorithms for finding solutions would extend the range of possible applications. Quantum strategies, being qubits, can be teleported but are immune from cloning - therefore extreme privacy of the agent’s activity could in principle be guaranteed. Then we point out some key problems that have to be solved before commercial use would be possible. With present technology, optical networks, single photon sources and detectors seems to be sufficient for an experimental realization in the near future.

  1. Bayesian Auctions with Friends and Foes

    NASA Astrophysics Data System (ADS)

    Chen, Po-An; Kempe, David

    We study auctions whose bidders are embedded in a social or economic network. As a result, even bidders who do not win the auction themselves might derive utility from the auction, namely, when a friend wins. On the other hand, when an enemy or competitor wins, a bidder might derive negative utility. Such spite and altruism will alter the bidding strategies. A simple and natural model for bidders’ utilities in these settings posits that the utility of a losing bidder i as a result of bidder j winning is a constant (positive or negative) fraction of bidder j’s utility.

  2. Auction-based distributed efficient economic operations of microgrid systems

    NASA Astrophysics Data System (ADS)

    Zou, Suli; Ma, Zhongjing; Liu, Xiangdong

    2014-12-01

    This paper studies the economic operations of the microgrid in a distributed way such that the operational schedule of each of the units, like generators, load units, storage units, etc., in a microgrid system, is implemented by autonomous agents. We apply and generalise the progressive second price (PSP) auction mechanism which was proposed by Lazar and Semret to efficiently allocate the divisible network resources. Considering the economic operation for the microgrid systems, the generators play as sellers to supply energy and the load units play as the buyers to consume energy, while a storage unit, like battery, super capacitor, etc., may transit between buyer and seller, such that it is a buyer when it charges and becomes a seller when it discharges. Furthermore in a connected mode, each individual unit competes against not only the other individual units in the microgrid but also the exogenous main grid possessing fixed electricity price and infinite trade capacity; that is to say, the auctioneer assigns the electricity among all individual units and the main grid with respect to the submitted bid strategies of all individual units in the microgrid in an economic way. Due to these distinct characteristics, the underlying auction games are distinct from those studied in the literature. We show that under mild conditions, the efficient economic operation strategy is a Nash equilibrium (NE) for the PSP auction games, and propose a distributed algorithm under which the system can converge to an NE. We also show that the performance of worst NE can be bounded with respect to the system parameters, say the energy trading price with the main grid, and based upon that, the implemented NE is unique and efficient under some conditions.

  3. Shock interaction mechanisms on a double wedge at Mach 7

    NASA Astrophysics Data System (ADS)

    Durna, Ahmet Selim; El Hajj Ali Barada, Mohamad; Celik, Bayram

    2016-09-01

    Present computational study investigates formation and interaction mechanisms of shocks and boundary layer for low enthalpy Mach 7 flows of nitrogen over double wedges, which have fixed fore and various aft angles of 30° and 45°-60°, respectively. We use a density based finite-volume Navier-Stokes solver to simulate low enthalpy Mach 7 flows of nitrogen over double wedges. The solver is first and second order accurate in time and space, respectively. The meshes used in simulations of two-dimensional laminar flows consist of multiple blocks of structured mesh. Depending on the intensity, impingement angle, and impingement location of transmitted shock wave, the resulting adverse pressure gradient related disturbances on the wedge surface can trigger complex flow physics both in subsonic and supersonic regions. We observe a strong interaction between the deformation of the boundary layer and the bow shock as well as the transmitted shock for high aft angles. Comparison of the obtained results in terms of general flow physics shows that there exists an aft angle threshold value for such interaction which is in the range of 45°-50°.

  4. Double-peak mechanical properties of carbon-nanotube fibers.

    PubMed

    Zhao, Jingna; Zhang, Xiaohua; Di, Jiangtao; Xu, Geng; Yang, Xiaojie; Liu, Xiangyang; Yong, Zhenzhong; Chen, Minghai; Li, Qingwen

    2010-11-22

    The introduction of twist during the spinning of carbon nanotubes from their arrays (forests) has been widely applied in making ultrastrong, stiff, and lightweight nanotube fibers. Here, for the first time, an important observation of a double-peak behavior of the tensile properties, as a function of the twist angle, that is different from the single peak of traditional fibers is reported. Raman spectra show that the new peak arises from the collapse of nanotubes, showing a strong "nano" element in applying the ancient draw-and-twist technique, besides the downsizing. A qualitative continuum model is also presented to describe the collapse-induced enhancement as well as traditional fibers. Our combined experimental and theoretical studies indicate the direction of full utilization of the nano element in improving the mechanical properties of nanotube fibers. PMID:20941775

  5. Double-exchange mechanism for CrO2

    NASA Astrophysics Data System (ADS)

    Schlottmann, P.

    2003-05-01

    Band-structure calculations predict a gap of 1.5 eV in the minority-spin density of states of the half-metallic ferromagnet CrO2. The magnitude of TC, the magnons, and the activation gap in the resistivity cannot be explained with this band picture. We propose a double-exchange mechanism for two electrons per Cr site invoking strong Hund’s rule correlations and the distortion in the CrO6 octahedra, which localize one electron into the xy orbital at each Cr site, while the electrons in the xz and yz orbitals are itinerant. The effective exchange interaction naturally leads to a ferromagnetic ground state with low-energy magnon excitations and several branches of excitations separated by energy gaps from the ground state, reducing TC. Quantum fluctuations suppress the orbital long-range order, giving rise to an orbital resonant valence bond-type ground state.

  6. 77 FR 38803 - Mobility Fund Phase I Auction Updated Data For Auction 901

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-29

    ... Public Notice, 77 FR 32092, May 31, 2012, the Bureaus described how they identified census blocks... COMMISSION Mobility Fund Phase I Auction Updated Data For Auction 901 AGENCY: Federal Communications... Competition Bureaus (Bureaus) announce updated data files of census blocks eligible for the Mobility...

  7. Mechanisms underlying strong-field double ionization of argon dimers

    SciTech Connect

    Manschwetus, B.; Rottke, H.; Steinmeyer, G.; Sandner, W.; Foucar, L.; Czasch, A.; Schmidt-Boecking, H.

    2010-07-15

    We investigate double ionization of argon dimers in high-intensity ultrashort Ti:sapphire laser pulses. We are able to identify several strong-field excitation pathways of the dimer that terminate in atomic ion pairs from a Coulomb explosion. The explosion starts from two-site double-ionized dimers and from one-site double-ionized ones after radiative charge transfer at small internuclear separation. One-site double ionization is accomplished by laser-induced charge transfer in the high-intensity laser pulse following two-site double ionization. The highest energy ion pairs we observed can be attributed to ''frustrated triple ionization'' of the argon dimer.

  8. Analysis of femtosecond quantum control mechanisms with colored double pulses

    SciTech Connect

    Vogt, Gerhard; Nuernberger, Patrick; Selle, Reimer; Dimler, Frank; Brixner, Tobias; Gerber, Gustav

    2006-09-15

    Fitness landscapes based on a limited number of laser pulse shape parameters can elucidate reaction pathways and can help to find the underlying control mechanism of optimal pulses determined by adaptive femtosecond quantum control. In a first experiment, we employ colored double pulses and systematically scan both the temporal subpulse separation and the relative amplitude of the two subpulses to acquire fitness landscapes. Comparison with results obtained from a closed-loop experiment demonstrates the capability of fitness landscapes for the revelation of possible control mechanisms. In a second experiment, using transient absorption spectroscopy, we investigate and compare the dependence of the excitation efficiency of the solvated dye molecule 5,5{sup '}-dichloro-11-diphenylamino-3,3{sup '}-diethyl-10,12-ethylene thiatricarbocyanine perchlorate (IR140) on selected pulse shapes in two parametrizations. The results show that very different pulse profiles can be equivalently adequate to maximize a given control objective. Fitness landscapes thus provide valuable information about different pathways along which a molecular system can be controlled with shaped laser pulses.

  9. Design Implications of Real-Time Feedback in Continuous Combinatorial Auctions: An Experimental Investigation

    ERIC Educational Resources Information Center

    Sanyal, Pallab

    2009-01-01

    Information Technology (IT) has spawned the growth of novel and innovative market mechanisms (such as online auctions) and associated businesses (such as eBay and Priceline) that were not feasible without the capabilities and reach of these modern information technologies. Previous studies on designing trading mechanisms for online markets…

  10. Auctionable fixed transmission rights for congestion management

    NASA Astrophysics Data System (ADS)

    Alomoush, Muwaffaq Irsheid

    the transaction by the ISO, take a decision to expand the existing system, or retain the original structure of the system. Also, the thesis investigates the impact of wheeling transactions on congestion management, where we present a generalized mathematical model for the Fixed Transmission Right (FTR) auction. The auction guarantees FTR availability to all participants on a non-discriminatory basis, in which system users are permitted to buy, sell and trade FTRs through an auction. When FTRs are utilized with LMPs, they increase the efficient use of the transmission system and let a transmission customer gain advantageous features such as acquiring a mechanism to offset the extra cost due to congestion charges, providing financial and operational certainty and making system users pay for the actual use of the congested paths. The thesis also highlighted FTR trading in secondary markets to self-arrange access across different paths, create long-term transmission rights and provide more commercial certainty.

  11. Double Higgs mechanisms, supermassive stable particles and the vacuum energy

    NASA Astrophysics Data System (ADS)

    Santillán, Osvaldo P.; Gabbanelli, Luciano

    2016-07-01

    In the present work, a hidden scenario which cast a long-lived superheavy particle A0 and simultaneously an extremely light particle a with mass ma ˜ 10‑32-10‑33 eV is presented. The potential energy V (a) of the particle a models the vacuum energy density of the universe ρc ≃ 10‑47GeV4. On the other hand, the A0 particle may act as superheavy dark matter at present times and the products of its decay may be observed in high energy cosmic ray events. The hidden sector proposed here include light fermions with masses near the neutrino mass mν ˜ 10‑2 eV and superheavy ones with masses of the order of the GUT scale, interacting through a hidden SU(2)L interaction which also affects the ordinary sector. The construction of such combined scenario is nontrivial since the presence of light particles may spoil the stability of the heavy particle A0. However, double Higgs mechanisms may be helpful for overcoming this problem. In this context, the stability of the superheavy particle A0 is ensured due to chiral symmetry arguments elaborated in the text.

  12. Fluid mechanics of DNA double-strand filter elution.

    PubMed Central

    Rudinger, George; Blazek, Ed Robert

    2002-01-01

    Measurement of infrequent DNA double-strand breaks (DSB) in mammalian cells is essential for the understanding of cell damage by ionizing radiation and many DNA-reactive drugs. One of the most important assays for measuring DSB in cellular DNA is filter elution. This study is an attempt to determine whether standard concepts of fluid mechanics can yield a self-consistent model of this process. Major assumptions of the analysis are reptation through a channel formed by surrounding strands, with only strand ends captured by filter pores. Both viscosity and entanglement with surrounding strands are considered to determine the resistance to this motion. One important result is that the average elution time of a strand depends not only on its length, but also on the size distribution of the surrounding strands. This model is consistent with experimental observations, such as the dependence of elution kinetics upon radiation dose, but independence from the size of the DNA sample up to a critical filter loading, and possible overlap of elution times for strands of different length. It indicates how the dependence of elution time on the flow rate could reveal the relative importance of viscous and entanglement resistance, and also predicts the consequences of using different filters. PMID:11751292

  13. Double Higgs mechanisms, supermassive stable particles and the vacuum energy

    NASA Astrophysics Data System (ADS)

    Santillán, Osvaldo P.; Gabbanelli, Luciano

    2016-07-01

    In the present work, a hidden scenario which cast a long-lived superheavy particle A0 and simultaneously an extremely light particle a with mass ma ˜ 10-32-10-33 eV is presented. The potential energy V (a) of the particle a models the vacuum energy density of the universe ρc ≃ 10-47GeV4. On the other hand, the A0 particle may act as superheavy dark matter at present times and the products of its decay may be observed in high energy cosmic ray events. The hidden sector proposed here include light fermions with masses near the neutrino mass mν ˜ 10-2 eV and superheavy ones with masses of the order of the GUT scale, interacting through a hidden SU(2)L interaction which also affects the ordinary sector. The construction of such combined scenario is nontrivial since the presence of light particles may spoil the stability of the heavy particle A0. However, double Higgs mechanisms may be helpful for overcoming this problem. In this context, the stability of the superheavy particle A0 is ensured due to chiral symmetry arguments elaborated in the text.

  14. 41 CFR 102-38.95 - What is an auction?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false What is an auction? 102... Sales Process Competitive Sales § 102-38.95 What is an auction? An auction is a sale where the bid... sale. Normally, the bidder with the highest bid at the close of each bidding process is awarded...

  15. 41 CFR 102-38.95 - What is an auction?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 false What is an auction? 102... Sales Process Competitive Sales § 102-38.95 What is an auction? An auction is a sale where the bid... sale. Normally, the bidder with the highest bid at the close of each bidding process is awarded...

  16. 41 CFR 102-38.95 - What is an auction?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false What is an auction? 102... Sales Process Competitive Sales § 102-38.95 What is an auction? An auction is a sale where the bid... sale. Normally, the bidder with the highest bid at the close of each bidding process is awarded...

  17. 41 CFR 102-38.95 - What is an auction?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false What is an auction? 102... Sales Process Competitive Sales § 102-38.95 What is an auction? An auction is a sale where the bid... sale. Normally, the bidder with the highest bid at the close of each bidding process is awarded...

  18. Physical mechanism of current-free double layers

    SciTech Connect

    Chen, Francis F.

    2006-03-15

    Undriven double layers observed in plasmas expanding along magnetic fields are the result of a sheath instability connected with the Bohm criterion. Diverging magnetic field lines cause the presheath acceleration of ions, causing a potential jump resembling that of a double layer. The process stops when it runs out of energy.

  19. Bidding Agents That Perpetrate Auction Fraud

    NASA Astrophysics Data System (ADS)

    Trevathan, Jarrod; McCabe, Alan; Read, Wayne

    This paper presents a software bidding agent that inserts fake bids on the seller's behalf to inflate an auction's price. This behaviour is referred to as shill bidding. Shill bidding is strictly prohibited by online auctioneers, as it defrauds unsuspecting buyers by forcing them to pay more for the item. The malicious bidding agent was constructed to aid in developing shill detection techniques. We have previously documented a simple shill bidding agent that incrementally increases the auction price until it reaches the desired profit target, or it becomes too risky to continue bidding. This paper presents an adaptive shill bidding agent which when used over a series of auctions with substitutable items, can revise its strategy based on bidding behaviour in past auctions. The adaptive agent applies a novel prediction technique referred to as the Extremum Consistency (EC) algorithm, to determine the optimal price to aspire for. The EC algorithm has successfully been used in handwritten signature verification for determining the maximum and minimum values in an input stream. The agent's ability to inflate the price has been tested in a simulated marketplace and experimental results are presented.

  20. 77 FR 57085 - Mobility Fund Phase I Auction; Release of Files with Recalculated Road Miles for Auction 901...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-17

    .../ecfs/ . 1. In the Auction 901 Procedures Public Notice, 77 FR 32092, May 31, 2012, the Bureaus... Notice, 77 FR 7152, February 10, 2012, in calculating the number of road miles associated with each... COMMISSION Mobility Fund Phase I Auction; Release of Files with Recalculated Road Miles for Auction 901;...

  1. Double exchange mechanism for CrO_2

    NASA Astrophysics Data System (ADS)

    Schlottmann, P.

    2003-03-01

    CrO2 is a half-metallic ferromagnet with a Curie temperature of about 400 K and a saturation magnetization of 2.0 μB per Cr ion. The low T magnetization follows the T^3/2 dependence expected from magnons and the resistivity has a T^2 dependence superimposed to an Arrhenius law with an activation energy of 90 K. LSDA band structure calculations predict a gap of 1.5 eV in the minority spin density of states. The magnitude of T_c, the magnons and the activation gap cannot be explained with this band picture. We propose a double exchange mechanism for two electrons per Cr site invoking strong Hund's rule correlations and the distortion in the CrO6 octahedra, which localize one electron into the xy orbital at each Cr site, while the electrons in the xz and yz orbitals are itinerant. The effective exchange interaction naturally leads to a ferromagnetic ground state with low-energy magnon excitations and several branches of excitations separated by energy gaps from the ground state, reducing T_c. A strong depolarization as a function of T is also expected. Quantum fluctuations suppress the orbital long range order, giving rise to an orbital RVB-type ground state. Work supported by DARPA through ONR under contract No. MDA972-02-1-0002. Support by NSF under grant No. DMR01-05431 and DOE under grant No. DE-FG02-98ER45797 is also acknowledged.

  2. Reciprocity in Online Markets: Empirical Studies of Auction and Barter Markets

    ERIC Educational Resources Information Center

    Ye, Shun

    2013-01-01

    My dissertation seeks to understand how reciprocity affects transaction outcomes and mechanism design in online markets. The first essay examines negative reciprocity illustrated as feedback-revoking behavior in the eBay auction market, focusing on its impact and implications for reputation system design. I utilize the biggest policy change of…

  3. China’s Land Market Auctions: Evidence of Corruption?

    PubMed Central

    Cai, Hongbin; Henderson, J. Vernon; Zhang, Qinghua

    2013-01-01

    This paper studies the urban land market in China in 2003—2007. In China, all urban land is owned by the state. Leasehold use rights for land for (re)development are sold by city governments and are a key source of city revenue. Leasehold sales are viewed as a major venue for corruption, prompting a number of reforms over the years. Reforms now require all leasehold rights be sold at public auction. There are two main types of auction: regular English auction and an unusual type which we call a “two stage auction”. The latter type of auction seems more subject to corruption, and to side deals between potential bidders and the auctioneer. Absent corruption, theory suggests that two stage auctions would most likely maximize sales revenue for properties which are likely to have relatively few bidders, or are “cold”, which would suggest negative selection on property unobservables into such auctions. However, if such auctions are more corruptible, that could involve positive selection as city officials divert hotter properties to a more corruptible auction form. The paper finds that, overall, sales prices are lower for two stage auctions, and there is strong evidence of positive selection. The price difference is explained primarily by the fact that two stage auctions typically have just one bidder, or no competition despite the vibrant land market in Chinese cities. PMID:25506125

  4. 47 CFR 1.2208 - Public notice of auction completion and auction results.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... PROCEDURE Grants by Random Selection Competitive Bidding Proceedings Broadcast Television Spectrum Reverse... broadcast television spectrum incentive auction conducted under section 6403 of the Spectrum Act, public... indicate that the reassignments of television channels and reallocations of broadcast television...

  5. Mechanisms of Strong-Field Double Ionization of Xe

    NASA Astrophysics Data System (ADS)

    Sun, Xufei; Li, Min; Ye, Difa; Xin, Guoguo; Fu, Libin; Xie, Xiguo; Deng, Yongkai; Wu, Chengyin; Liu, Jie; Gong, Qihuang; Liu, Yunquan

    2014-09-01

    We perform a fully differential measurement on strong-field double ionization of Xe by 25 fs, 790 nm laser pulses in intensity region (0.4-3)×1014 W/cm2. We observe that the two-dimensional correlation momentum spectra along the laser polarization direction show a nonstructured distribution for double ionization of Xe when decreasing the laser intensity from 3×1014 to 4×1013 W /cm2. The electron correlation behavior is remarkably different with the low-Z rare gases, i.e., He, Ne, and Ar. We find that the electron energy cutoffs increase from 2.9Up to 7.8Up when decreasing the laser intensities from the sequential double ionization to the nonsequential double ionization regime. The experimental observation indicates that multiple rescatterings play an important role for the generation of high energy photoelectrons. We have further studied the shielding effect on the strong-field double ionization of high-Z atoms.

  6. Deformation effect simulation and optimization for double front axle steering mechanism

    NASA Astrophysics Data System (ADS)

    Wu, Jungang; Zhang, Siqin; Yang, Qinglong

    2013-03-01

    This paper research on tire wear problem of heavy vehicles with Double Front Axle Steering Mechanism from the flexible effect of Steering Mechanism, and proposes a structural optimization method which use both traditional static structural theory and dynamic structure theory - Equivalent Static Load (ESL) method to optimize key parts. The good simulated and test results show this method has high engineering practice and reference value for tire wear problem of Double Front Axle Steering Mechanism design.

  7. 43 CFR 2546.4 - Public auctions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Public auctions. 2546.4 Section 2546.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) COLOR-OF-TITLE AND OMITTED LANDS Snake...

  8. 43 CFR 2546.4 - Public auctions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Public auctions. 2546.4 Section 2546.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) COLOR-OF-TITLE AND OMITTED LANDS Snake...

  9. 43 CFR 2546.4 - Public auctions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Public auctions. 2546.4 Section 2546.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) COLOR-OF-TITLE AND OMITTED LANDS Snake...

  10. 43 CFR 2546.4 - Public auctions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Public auctions. 2546.4 Section 2546.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) COLOR-OF-TITLE AND OMITTED LANDS Snake...

  11. Books at Auction: The Art of Deaccessioning.

    ERIC Educational Resources Information Center

    Model, Peter

    1981-01-01

    Lack of space and budget cuts force many libraries to weed out books and to be selective in accepting collection bequests. The approach for deciding which books to weed out and whether to dispose of these books through dealers or auctions are decisions private clubs and many libraries must make. (RBF)

  12. 7 CFR 46.25 - Auction sales.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... companies which publish catalogs of offerings will be responsible for furnishing the auction company for... for sale by an owner, his name shall be shown in the catalog listing as owner. When a joint account... catalog a shipment without disclosing true ownership, if known, or the name of an agent's principal,...

  13. 7 CFR 46.25 - Auction sales.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... companies which publish catalogs of offerings will be responsible for furnishing the auction company for... for sale by an owner, his name shall be shown in the catalog listing as owner. When a joint account... catalog a shipment without disclosing true ownership, if known, or the name of an agent's principal,...

  14. 7 CFR 46.25 - Auction sales.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... companies which publish catalogs of offerings will be responsible for furnishing the auction company for... for sale by an owner, his name shall be shown in the catalog listing as owner. When a joint account... catalog a shipment without disclosing true ownership, if known, or the name of an agent's principal,...

  15. 19 CFR 127.34 - Auctioneer's commissions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Auctioneer's commissions. 127.34 Section 127.34 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY GENERAL ORDER, UNCLAIMED, AND ABANDONED MERCHANDISE Proceeds of Sale § 127.34...

  16. Experiments in Deaccessioning: Archives and Online Auctions.

    ERIC Educational Resources Information Center

    Doylen, Michael

    2001-01-01

    Discussion of the need for archives to remove duplicate or unneeded materials from their collection focuses on the legal and ethical issues raised for archives by the use of online auction venues in deaccessioning unwanted materials, based on experiences at the University of Wisconsin. (Author/LRW)

  17. Shell model nuclear matrix elements for competing mechanisms contributing to double beta decay

    SciTech Connect

    Horoi, Mihai

    2013-12-30

    Recent progress in the shell model approach to the nuclear matrix elements for the double beta decay process are presented. This includes nuclear matrix elements for competing mechanisms to neutrionless double beta decay, a comparison between closure and non-closure approximation for {sup 48}Ca, and an updated shell model analysis of nuclear matrix elements for the double beta decay of {sup 136}Xe.

  18. Elucidating the mechanisms of double ionization using intense half-cycle, single-cycle, and double half-cycle pulses

    SciTech Connect

    Kamta, G. Lagmago; Starace, Anthony F.

    2003-10-01

    We investigate the interaction of a two-active electron system (Li{sup -}) with intense single-cycle and double half-cycle pulses. The 'intensity' and 'frequency' considered correspond to the 'multiphoton above-barrier regime'. For the single-cycle pulse (SCP), the electric field changes sign once, allowing electron wave packets created during the first half cycle to recollide with the parent ion when driven back by the field. For the double half-cycle pulse (DHP), however, the electric field does not change sign, and electron wave packets created during the first half cycle are not driven back to the parent ion. We find that both single and double ionization are significantly larger for the SCP than for the DHP, thereby elucidating the role of the rescattering mechanism. On the other hand, doubly ionized electrons produced by a half-cycle pulse and a DHP are found to have angular distributions in which one electron is ejected in the direction of the pulse field, and the other in the opposite direction. This clear signature of electron correlations suggests that 'shake-off', 'knockout', and, possibly, 'multiphoton-sharing' processes are alternative contributing mechanisms for double ionization in this regime.

  19. The Double-Well Potential in Quantum Mechanics: A Simple, Numerically Exact Formulation

    ERIC Educational Resources Information Center

    Jelic, V.; Marsiglio, F.

    2012-01-01

    The double-well potential is arguably one of the most important potentials in quantum mechanics, because the solution contains the notion of a state as a linear superposition of "classical" states, a concept which has become very important in quantum information theory. It is therefore desirable to have solutions to simple double-well potentials…

  20. The role of the EPA auctions in the SO{sub 2} allowance market: What the first two auctions revealed

    SciTech Connect

    Critchfield, L.R.

    1995-12-31

    Title IV of the Clean Air Act Amendments of 1990 created a market-based trading program to reduce sulfur dioxide emissions from electric power plants. In order to stimulate and support this new market, the Act provided for the annual auction of a small portion of the total emission allowances allocated to utilities each year. This paper discusses how the first EPA auctions in 1993 played a large role in creating market value for allowances while the second more accurately reflected market demand. Also addressed is how the market has responded to the design of the auctions and the government rules associated with these auctions. In addition, the paper mentions the role of the Chicago Board of Trade in administering and establishing a market for the EPA auctions and what the future of the EPA auctions may be.

  1. Auction design and the market for sulfur dioxide emissions

    SciTech Connect

    Joskow, P.L.; Schmalensee, R.; Bailey, E.M.

    1997-12-31

    Title IV of the Clean Air Act Amendments of 1990 created a market for electric utility emissions of sulfur dioxide (SO{sub 2}). Recent papers have argued that flaws in the design of the auctions that are part of this market have adversely affected its performance. These papers incorrectly assume that trade can only occur at auctions, however. Our empirical analysis of the SO{sub 2} emissions market shows that the auctions have become a small part of a relatively efficient market and that the auction design problems that have attracted the most attention have had no effect on actual market prices.

  2. Auctions vs negotiations: a study of price differentials.

    PubMed

    Kjerstad, Egil

    2005-12-01

    Recent contributions in auction and bargaining theory suggest that a procurer should place more faith in the power of competition among alternative suppliers than in his or her own negotiating skill. Based on data from 216 contracts between procurers and suppliers of medical and surgical articles, we test whether auctions and bargaining result in significantly different prices. The main results are that auctions give 'thicker' markets compared with negotiations, as expected, but that auctions do not result in significantly lower prices compared with negotiations. PMID:15945037

  3. The effect of stabilizer on the mechanical response of double-emulsion-templated polymersomes.

    PubMed

    Jang, Woo-Sik; Park, Seung Chul; Kim, Miju; Doh, Junsang; Lee, Daeyeon; Hammer, Daniel A

    2015-02-01

    Recent studies have shown that polymersomes templated by microfluidic double-emulsion possess several advantages such as high monodispersity and encapsulation efficiency compared with those generated based on thin-film rehydration and electroformation. Stabilizers, including bovine serum albumin (BSA) and polyvinyl alcohol (PVA), have been used to enhance the formation and stability of double emulsions that are used as templates for the generation of polymersomes. In this work, the effect of stabilizers on the mechanical response of double-emulsion-templated polymersomes using micropipette aspiration is investigated. It is demonstrated that the existence of stabilizers results in the inelastic response in poly-mersomes in the early stage of solvent removal. However, aged polymersomes that have little residual solvent show elastic behavior. Polymersomes prepared from PVA-stabilized double emulsions have noticeably lower area expansion moduli than polymersomes prepared from stabilizer-free and BSA-stabilized double emulsions, suggesting that PVA is incorporated in the bilayer membrane of polymersomes.

  4. Health Auctions: a Valuation Experiment (HAVE) study protocol

    PubMed Central

    Kularatna, Sanjeewa; Petrie, Dennis; Scuffham, Paul A; Byrnes, Joshua

    2016-01-01

    Introduction Quality-adjusted life years are derived using health state utility weights which adjust for the relative value of living in each health state compared with living in perfect health. Various techniques are used to estimate health state utility weights including time-trade-off and standard gamble. These methods have exhibited limitations in terms of complexity, validity and reliability. A new composite approach using experimental auctions to value health states is introduced in this protocol. Methods and analysis A pilot study will test the feasibility and validity of using experimental auctions to value health states in monetary terms. A convenient sample (n=150) from a population of university staff and students will be invited to participate in 30 auction sets with a group of 5 people in each set. The 9 health states auctioned in each auction set will come from the commonly used EQ-5D-3L instrument. At most participants purchase 2 health states, and the participant who acquires the 2 ‘best’ health states on average will keep the amount of money they do not spend in acquiring those health states. The value (highest bid and average bid) of each of the 24 health states will be compared across auctions to test for reliability across auction groups and across auctioneers. A test retest will be conducted for 10% of the sample to assess reliability of responses for health states auctions. Feasibility of conducting experimental auctions to value health states will also be examined. The validity of estimated health states values will be compared with published utility estimates from other methods. This pilot study will explore the feasibility, reliability and validity in using experimental auction for valuing health states. Ethics and dissemination Ethical clearance was obtained from Griffith University ethics committee. The results will be disseminated in peer-reviewed journals and major international conferences. PMID:27056589

  5. ``Quasi-complete'' mechanical model for a double torsion pendulum

    NASA Astrophysics Data System (ADS)

    De Marchi, Fabrizio; Pucacco, Giuseppe; Bassan, Massimo; De Rosa, Rosario; Di Fiore, Luciano; Garufi, Fabio; Grado, Aniello; Marconi, Lorenzo; Stanga, Ruggero; Stolzi, Francesco; Visco, Massimo

    2013-06-01

    We present a dynamical model for the double torsion pendulum nicknamed “PETER,” where one torsion pendulum hangs in cascade, but off axis, from the other. The dynamics of interest in these devices lies around the torsional resonance, that is at very low frequencies (mHz). However, we find that, in order to properly describe the forced motion of the pendulums, also other modes must be considered, namely swinging and bouncing oscillations of the two suspended masses, that resonate at higher frequencies (Hz). Although the system has obviously 6+6 degrees of freedom, we find that 8 are sufficient for an accurate description of the observed motion. This model produces reliable estimates of the response to generic external disturbances and actuating forces or torques. In particular, we compute the effect of seismic floor motion (“tilt” noise) on the low frequency part of the signal spectra and show that it properly accounts for most of the measured low frequency noise.

  6. Non-double-couple earthquake mechanisms at the Geysers geothermal area, California

    USGS Publications Warehouse

    Ross, A.; Foulger, G.R.; Julian, B.R.

    1996-01-01

    Inverting P- and S-wave polarities and P:SH amplitude ratios using linear programming methods suggests that about 20% of earthquakes at The Geysers geothermal area have significantly non-double-couple focal mechanisms, with explosive volumetric components as large as 33% of the seismic moment. This conclusion contrasts with those of earlier studies, which interpreted data in terms of double couples. The non-double-couple mechanisms are consistent with combined shear and tensile faulting, possibly caused by industrial water injection. Implosive mechanisms, which might be expected because of rapid steam withdrawal, have not been found. Significant compensated-linear-vector-dipole (CLVD) components in some mechanisms may indicate rapid fluid flow accompanying crack opening. Copyright 1996 by the American Geophysical Union.

  7. A Combinatorial Auction Based Algorithm for Flexible Seat Reservation Systems

    NASA Astrophysics Data System (ADS)

    Otomura, Kazutoshi; Tomii, Norio

    We present algorithms for flexible seat distribution problems, which is defined as a problem to give an appropriate travel plan to each passenger after receiving their requests concerning their travel demands. Seat distribution problems occur when a flexible seat reservation system is implemented in which passengers are allowed to reserve seats by submitting their demands instead of specifying trains. To solve the seat distribution problem, we have formalized it as a winner determination problem of the combinatorial auction mechanism. It should be noted that difficulty of the seat distribution problem varies depending on instances of the problem, because the number of demands often varies and users' requests sometimes converge on particular trains. This suggests that in order to get solutions with high quality, algorithms that appropriately control the search space are indispensable. In this paper, we present three kinds of such algorithms for the seat distribution problem together with the results of several experiments.

  8. A Classroom Auction with Externalities: Applied to Mergers and Acquisitions

    ERIC Educational Resources Information Center

    Meister, J. Patrick; Anderson, Kyle J.

    2007-01-01

    The authors describe an in-class exercise in which students participate in an auction to buy US Airways. The exercise is based on events of late 1995, in which neither United nor American Airlines decided to bid for US Airways. Two teams of students participate in an English auction. Students learn that the equilibrium of the sequential game is…

  9. A Trustworthy Internet Auction Model with Verifiable Fairness.

    ERIC Educational Resources Information Center

    Liao, Gen-Yih; Hwang, Jing-Jang

    2001-01-01

    Describes an Internet auction model achieving verifiable fairness, a requirement aimed at enhancing the trust of bidders in auctioneers. Analysis results demonstrate that the proposed model satisfies various requirements regarding fairness and privacy. Moreover, in the proposed model, the losing bids remain sealed. (Author/AEF)

  10. A Combinatorial Auction among Versatile Experts and Amateurs

    NASA Astrophysics Data System (ADS)

    Ito, Takayuki; Yokoo, Makoto; Matsubara, Shigeo

    Auctions have become an integral part of electronic commerce and a promising field for applying multi-agent technologies. Correctly judging the quality of auctioned goods is often difficult for amateurs, in particular, in Internet auctions. However, experts can correctly judge the quality of goods. In this situation, it is difficult to make experts tell the truth and attain an efficient allocation, since experts have a clear advantage over amateurs and they would not reveal their valuable information without some reward. In our previous work, we have succeeded in developing such auction protocols under the following two cases: (1) the case of a single-unit auction among experts and amateurs, and (2) the case of a combinatorial auction among single-skilled experts and amateurs. In this paper, we focus on versatile experts. Versatile experts have an interest in, and expert knowledge on the qualities of several goods. In the case of versatile experts, there would be several problems, e.g., free riding problems, if we simply extended the previous VCG-style auction protocol. Thus, in this paper, we employ PORF (price-oriented, rationing-free) protocol for designing our new protocol to realize a strategy-proof auction protocol for experts. In the protocol, the dominant strategy for experts is truth-telling. Also, for amateurs, truth-telling is the best response when two or more experts select the dominant strategy. Furthermore, the protocol is false-name-proof.

  11. 75 FR 8070 - Closed Auction of Broadcast Construction Permits Scheduled for July 20, 2010; Auction 88...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... announces the auction of certain broadcast FM, AM, and FM Translator construction permits scheduled to... certain broadcast FM, AM, and FM Translator construction permits and sought comment on the procedures to... resolve mutual exclusivity between applications for new AM stations on 640 kHz and 1230 kHz in the...

  12. Detecting Fraud in Internet Auction Systems

    NASA Astrophysics Data System (ADS)

    Peng, Yanlin; Zhang, Linfeng; Guan, Yong

    Fraud compromises the thriving Internet auction market. Studies have shown that fraudsters often manipulate their reputations through sophisticated collusions with accomplices, enabling them to defeat the reputation-based feedback systems that are used to combat fraud. This paper presents an algorithm that can identify colluding fraudsters in real time. Experiments with eBay transaction data show that the algorithm has low false negative and false positive rates. Furthermore, the algorithm can identify fraudsters who are innocent at the time of the data collection, but engage in fraudulent transactions soon after they accumulate good feedback ratings.

  13. Rationality, irrationality and escalating behavior in lowest unique bid auctions.

    PubMed

    Radicchi, Filippo; Baronchelli, Andrea; Amaral, Luís A N

    2012-01-01

    Information technology has revolutionized the traditional structure of markets. The removal of geographical and time constraints has fostered the growth of online auction markets, which now include millions of economic agents worldwide and annual transaction volumes in the billions of dollars. Here, we analyze bid histories of a little studied type of online auctions--lowest unique bid auctions. Similarly to what has been reported for foraging animals searching for scarce food, we find that agents adopt Lévy flight search strategies in their exploration of "bid space". The Lévy regime, which is characterized by a power-law decaying probability distribution of step lengths, holds over nearly three orders of magnitude. We develop a quantitative model for lowest unique bid online auctions that reveals that agents use nearly optimal bidding strategies. However, agents participating in these auctions do not optimize their financial gain. Indeed, as long as there are many auction participants, a rational profit optimizing agent would choose not to participate in these auction markets.

  14. Smarter than Others? Conjectures in Lowest Unique Bid Auctions

    PubMed Central

    Hu, Rui; Chen, Qinghua

    2015-01-01

    Research concerning various types of auctions, such as English auctions, Dutch auctions, highest-price sealed-bid auctions, and second-price sealed-bid auctions, is always a topic of considerable interest in interdisciplinary fields. The type of auction, known as a lowest unique bid auction (LUBA), has also attracted significant attention. Various models have been proposed, but they often fail to explain satisfactorily the real bid-distribution characteristics. This paper discusses LUBA bid-distribution characteristics, including the inverted-J shape and the exponential decrease in the upper region. The authors note that this type of distribution, which initially increases and later decreases, cannot be derived from the symmetric Nash equilibrium framework based on perfect information that has previously been used. A novel optimization model based on non-perfect information is presented. The kernel of this model is the premise that agents make decisions to achieve maximum profit based on imaginary information or assumptions regarding the behavior of others. PMID:25849631

  15. Physical mechanisms of active control of sound transmission through rib stiffened double-panel structure

    NASA Astrophysics Data System (ADS)

    Ma, Xiyue; Chen, Kean; Ding, Shaohu; Yu, Haoxin

    2016-06-01

    This paper presents an analytical investigation on physical mechanisms of actively controlling sound transmission through a rib stiffened double-panel structure using point source in the cavity. The combined modal expansion and vibro-acoustic coupling methods are applied to establish the theoretical model of such active structure. Under the condition of minimizing radiated power of the radiating ribbed plate, the physical mechanisms are interpreted in detail from the point of view of modal couplings similar as that used in existed literatures. Results obtained demonstrate that the rule of sound energy transmission and the physical mechanisms for the rib stiffened double-panel structure are all changed, and affected by the coupling effects of the rib when compared with the analytical results obtained for unribbed double-panel case. By taking the coupling effects of the rib into considerations, the cavity modal suppression and rearrangement mechanisms obtained in existed investigations are modified and supplemented for the ribbed plate case, which gives a clear interpretation for the physical nature involved in the active rib stiffened double-panel structure.

  16. The communications spectrum: Frequency allocations and auctions

    NASA Astrophysics Data System (ADS)

    Pritchard, Wilbur

    1997-01-01

    Demands on the communications spectrum have increased sharply because of the growth in radio communication services, the large bandwidths now required, and the rapid increases in world population. The problem will be exacerbated by the requirements of high definition television and the enormous amounts of information that will be transmitted by radio. The electromagnetic spectrum is a finite natural resource of great value used for emergency communications and military operations as well as for commercial purposes. Both government and the marketplace have proper roles in the allocation of its resources. There are no viable alternatives to international organizations such as the International Telecommunication Union or to agencies such as the Federal Communications Commission for the regulation of radio communication and the assignment of spectrum to essential public services. Although government auctions of spectrum are justifiable where there is no way to distinguish among commercial entities seeking to use the same bands for similar services, the practice is inherently inequitable and discourages development of new uses for the spectrum by removing investment protection. Recommended alternatives to auctions are: (1) lotteries, which keep assets and proceeds in the economy; and (2) ongoing charges for current as well as new users of the spectrum.

  17. Nonlinearity from quantum mechanics: Dynamically unstable Bose-Einstein condensate in a double-well trap

    SciTech Connect

    Javanainen, Juha

    2010-05-15

    We study theoretically an atomic Bose-Einstein condensate in a double-well trap, both quantum-mechanically and classically, under conditions such that in the classical model an unstable equilibrium dissolves into large-scale oscillations of the atoms between the potential wells. Quantum mechanics alone does not exhibit such nonlinear dynamics, but measurements of the atom numbers in the potential wells may nevertheless cause the condensate to behave essentially classically.

  18. Double-slit experiment with single wave-driven particles and its relation to quantum mechanics

    NASA Astrophysics Data System (ADS)

    Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Rosenlund Ahl, Sonja; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens T.; Bohr, Tomas

    2015-07-01

    In a thought-provoking paper, Couder and Fort [Phys. Rev. Lett. 97, 154101 (2006), 10.1103/PhysRevLett.97.154101] describe a version of the famous double-slit experiment performed with droplets bouncing on a vertically vibrated fluid surface. In the experiment, an interference pattern in the single-particle statistics is found even though it is possible to determine unambiguously which slit the walking droplet passes. Here we argue, however, that the single-particle statistics in such an experiment will be fundamentally different from the single-particle statistics of quantum mechanics. Quantum mechanical interference takes place between different classical paths with precise amplitude and phase relations. In the double-slit experiment with walking droplets, these relations are lost since one of the paths is singled out by the droplet. To support our conclusions, we have carried out our own double-slit experiment, and our results, in particular the long and variable slit passage times of the droplets, cast strong doubt on the feasibility of the interference claimed by Couder and Fort. To understand theoretically the limitations of wave-driven particle systems as analogs to quantum mechanics, we introduce a Schrödinger equation with a source term originating from a localized particle that generates a wave while being simultaneously guided by it. We show that the ensuing particle-wave dynamics can capture some characteristics of quantum mechanics such as orbital quantization. However, the particle-wave dynamics can not reproduce quantum mechanics in general, and we show that the single-particle statistics for our model in a double-slit experiment with an additional splitter plate differs qualitatively from that of quantum mechanics.

  19. Double-slit experiment with single wave-driven particles and its relation to quantum mechanics.

    PubMed

    Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Rosenlund Ahl, Sonja; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens T; Bohr, Tomas

    2015-07-01

    In a thought-provoking paper, Couder and Fort [Phys. Rev. Lett. 97, 154101 (2006)] describe a version of the famous double-slit experiment performed with droplets bouncing on a vertically vibrated fluid surface. In the experiment, an interference pattern in the single-particle statistics is found even though it is possible to determine unambiguously which slit the walking droplet passes. Here we argue, however, that the single-particle statistics in such an experiment will be fundamentally different from the single-particle statistics of quantum mechanics. Quantum mechanical interference takes place between different classical paths with precise amplitude and phase relations. In the double-slit experiment with walking droplets, these relations are lost since one of the paths is singled out by the droplet. To support our conclusions, we have carried out our own double-slit experiment, and our results, in particular the long and variable slit passage times of the droplets, cast strong doubt on the feasibility of the interference claimed by Couder and Fort. To understand theoretically the limitations of wave-driven particle systems as analogs to quantum mechanics, we introduce a Schrödinger equation with a source term originating from a localized particle that generates a wave while being simultaneously guided by it. We show that the ensuing particle-wave dynamics can capture some characteristics of quantum mechanics such as orbital quantization. However, the particle-wave dynamics can not reproduce quantum mechanics in general, and we show that the single-particle statistics for our model in a double-slit experiment with an additional splitter plate differs qualitatively from that of quantum mechanics.

  20. 78 FR 68839 - Tribal Mobility Fund Phase I Auction Rescheduled for February 25, 2014; Notice of Changes to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... requirements as set out in the Auction 902 Procedures Public Notice, 78 FR 56875, September 16, 2013, remain... to Auction 902: (1) A revised auction tutorial incorporating the revised dates and deadlines will...

  1. Auction fever: exploring informational social influences on bidder choices.

    PubMed

    Chen, Yi-Fen

    2011-01-01

    Previous investigations of herd behavior have identified the importance of informational social influences in consumer decision making. This research presents three studies examining herd behavior in online auctions. The three studies addressed the influence on bidder online choices of herd cues frequently found in online auctions, including bid number, feedback ratings, and number of questions and answers. This research also investigated the effect of different levels of herd cues on bidder online choices under high and low brand awareness in online auctions. The experimental results demonstrated that bidders use online herd cues when making decisions in online auctions. Additionally, different levels of herd cues influence bidder online choices in both high and low brand awareness product situations.

  2. Auction fever: exploring informational social influences on bidder choices.

    PubMed

    Chen, Yi-Fen

    2011-01-01

    Previous investigations of herd behavior have identified the importance of informational social influences in consumer decision making. This research presents three studies examining herd behavior in online auctions. The three studies addressed the influence on bidder online choices of herd cues frequently found in online auctions, including bid number, feedback ratings, and number of questions and answers. This research also investigated the effect of different levels of herd cues on bidder online choices under high and low brand awareness in online auctions. The experimental results demonstrated that bidders use online herd cues when making decisions in online auctions. Additionally, different levels of herd cues influence bidder online choices in both high and low brand awareness product situations. PMID:21192763

  3. 6. East rear, cattle auction arena below in background, Omaha ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. East rear, cattle auction arena below in background, Omaha livestock market offices above. View to west. - South Omaha Union Stock Yards, Stock Yards Autopark, 2900 "O" Plaza, Omaha, Douglas County, NE

  4. Document of the Month: Photograph of a Land Auction.

    ERIC Educational Resources Information Center

    Alexander, Mary

    1979-01-01

    Photograph of a land auction in Imperial, California, 1904, accompanied by a history of the federal government's policy on the distribution and development of publicly owned land. Suggestions for using the photograph as historical evidence are included. (KC)

  5. Double Switching of Two Rings in Palindromic [3]Pseudorotaxanes: Cooperativity and Mechanism of Motion.

    PubMed

    Benson, Christopher R; Share, Andrew I; Marzo, Matthew G; Flood, Amar H

    2016-04-18

    The existence of two rings in [3]pseudorotaxanes presents opportunities for those rings to undergo double switching and cooperative mechanical coupling. To investigate this capability, we identified a new strategy for bringing two rings into contact with each other and conducted mechanistic studies to reveal their kinetic cooperativity. A redox-active tetrazine ligand bearing two binding sites was selected to allow for two mobile copper(I) macrocycle ring moieties to come together. To realize this switching modality, ligands were screened against their ability to serve as stations on which the rings are initially parked, ultimately identifying 5,5'-dimethyl-2,2'-bipyridine. The kinetics of switching a macrocycle in a single-site [2]pseudorotaxane between bipyridine and single-site tetrazine stations were examined using electrochemistry. The forward movement was rate-limited by the bimolecular reaction between reduced tetrazine and bipyridine [2]pseudorotaxane. Two bipyridines were then used with a double-site tetrazine to verify double switching of two rings. Our results indicated stepwise movements, with the first ring moving 4 times more frequently (faster) than the second. While this behavior is indicative of anticooperative kinetics, positive thermodynamic cooperativity sets the two rings in motion even though just one tetrazine is reduced with one electron. Double switching in this [3]pseudorotaxane uniquely demonstrates how a series of independent thermodynamic states and kinetic paths govern an apparently simple mechanical motion. PMID:27050829

  6. [Arc spectrum diagnostic and heat coupling mechanism analysis of double wire pulsed MIG welding].

    PubMed

    Liu, Yong-qiang; Li, Huan; Yang, Li-jun; Zheng, Kai; Gao, Ying

    2015-01-01

    A double wire pulsed MIG welding test system was built in the present paper, in order to analyze the heat-coupling mechanism of double wire pulsed MIG welding, and study are temperature field. Spectroscopic technique was used in diagnostic analysis of the are, plasma radiation was collected by using hollow probe method to obtain the arc plasma optical signal The electron temperature of double wire pulsed MIG welding arc plasma was calculated by using Boltzmann diagram method, the electron temperature distribution was obtained, a comprehensive analysis of the arc was conducted combined with the high speed camera technology and acquisition means of electricity signal. The innovation of this paper is the combination of high-speed camera image information of are and optical signal of arc plasma to analyze the coupling mechanism for dual arc, and a more intuitive analysis for are temperature field was conducted. The test results showed that a push-pull output was achieved and droplet transfer mode was a drop in a pulse in the welding process; Two arcs attracted each other under the action of a magnetic field, and shifted to the center of the arc in welding process, so a new heat center was formed at the geometric center of the double arc, and flowing up phenomenon occurred on the arc; Dual arc electronic temperature showed an inverted V-shaped distribution overall, and at the geometric center of the double arc, the arc electron temperature at 3 mm off the workpiece surface was the highest, which was 16,887.66 K, about 4,900 K higher than the lowest temperature 11,963.63 K. PMID:25993809

  7. [Arc spectrum diagnostic and heat coupling mechanism analysis of double wire pulsed MIG welding].

    PubMed

    Liu, Yong-qiang; Li, Huan; Yang, Li-jun; Zheng, Kai; Gao, Ying

    2015-01-01

    A double wire pulsed MIG welding test system was built in the present paper, in order to analyze the heat-coupling mechanism of double wire pulsed MIG welding, and study are temperature field. Spectroscopic technique was used in diagnostic analysis of the are, plasma radiation was collected by using hollow probe method to obtain the arc plasma optical signal The electron temperature of double wire pulsed MIG welding arc plasma was calculated by using Boltzmann diagram method, the electron temperature distribution was obtained, a comprehensive analysis of the arc was conducted combined with the high speed camera technology and acquisition means of electricity signal. The innovation of this paper is the combination of high-speed camera image information of are and optical signal of arc plasma to analyze the coupling mechanism for dual arc, and a more intuitive analysis for are temperature field was conducted. The test results showed that a push-pull output was achieved and droplet transfer mode was a drop in a pulse in the welding process; Two arcs attracted each other under the action of a magnetic field, and shifted to the center of the arc in welding process, so a new heat center was formed at the geometric center of the double arc, and flowing up phenomenon occurred on the arc; Dual arc electronic temperature showed an inverted V-shaped distribution overall, and at the geometric center of the double arc, the arc electron temperature at 3 mm off the workpiece surface was the highest, which was 16,887.66 K, about 4,900 K higher than the lowest temperature 11,963.63 K.

  8. Interpreting nonlinear vibrational spectroscopy with the classical mechanical analogs of double-sided Feynman diagrams.

    PubMed

    Noid, W G; Loring, Roger F

    2004-10-15

    Observables in coherent, multiple-pulse infrared spectroscopy may be computed from a vibrational nonlinear response function. This response function is conventionally calculated quantum-mechanically, but the challenges in applying quantum mechanics to large, anharmonic systems motivate the examination of classical mechanical vibrational nonlinear response functions. We present an approximate formulation of the classical mechanical third-order vibrational response function for an anharmonic solute oscillator interacting with a harmonic solvent, which establishes a clear connection between classical and quantum mechanical treatments. This formalism permits the identification of the classical mechanical analog of the pure dephasing of a quantum mechanical degree of freedom, and suggests the construction of classical mechanical analogs of the double-sided Feynman diagrams of quantum mechanics, which are widely applied to nonlinear spectroscopy. Application of a rotating wave approximation permits the analytic extraction of signals obeying particular spatial phase matching conditions from a classical-mechanical response function. Calculations of the third-order response function for an anharmonic oscillator coupled to a harmonic solvent are compared to numerically correct classical mechanical results.

  9. 31 CFR 356.23 - How are the auction results announced?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... conclusion of the auction, we will announce the auction results through a press release that is available on our Web site at http://www.treasurydirect.gov. (b) The press release will include such information...

  10. 31 CFR 356.23 - How are the auction results announced?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... conclusion of the auction, we will announce the auction results through a press release that is available on our Web site at http://www.treasurydirect.gov. (b) The press release will include such information...

  11. 31 CFR 356.23 - How are the auction results announced?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) After the conclusion of the auction, we will announce the auction results through a press release that is available on our Web site at http://www.treasurydirect.gov. (b) The press release will...

  12. 31 CFR 356.23 - How are the auction results announced?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... conclusion of the auction, we will announce the auction results through a press release that is available on our Web site at http://www.treasurydirect.gov. (b) The press release will include such information...

  13. 31 CFR 356.23 - How are the auction results announced?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... conclusion of the auction, we will announce the auction results through a press release that is available on our Web site at http://www.treasurydirect.gov. (b) The press release will include such information...

  14. 75 FR 57947 - Auction of VHF Commercial Television Station Construction Permits Scheduled for February 15, 2011...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-23

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION Auction of VHF Commercial Television Station Construction Permits Scheduled for February 15, 2011; Comment Sought on Competitive Bidding Procedures for Auction 90 AGENCY: Federal Communications...

  15. Overlapping mechanisms promote postsynaptic RAD-51 filament disassembly during meiotic double-strand break repair.

    PubMed

    Ward, Jordan D; Muzzini, Diego M; Petalcorin, Mark I R; Martinez-Perez, Enrique; Martin, Julie S; Plevani, Paolo; Cassata, Giuseppe; Marini, Federica; Boulton, Simon J

    2010-01-29

    Homologous recombination (HR) is essential for repair of meiotic DNA double-strand breaks (DSBs). Although the mechanisms of RAD-51-DNA filament assembly and strand exchange are well characterized, the subsequent steps of HR are less well defined. Here, we describe a synthetic lethal interaction between the C. elegans helicase helq-1 and RAD-51 paralog rfs-1, which results in a block to meiotic DSB repair after strand invasion. Whereas RAD-51-ssDNA filaments assemble at meiotic DSBs with normal kinetics in helq-1, rfs-1 double mutants, persistence of RAD-51 foci and genetic interactions with rtel-1 suggest a failure to disassemble RAD-51 from strand invasion intermediates. Indeed, purified HELQ-1 and RFS-1 independently bind to and promote the disassembly of RAD-51 from double-stranded, but not single-stranded, DNA filaments via distinct mechanisms in vitro. These results indicate that two compensating activities are required to promote postsynaptic RAD-51 filament disassembly, which are collectively essential for completion of meiotic DSB repair.

  16. Mechanical and microstructural characterization of single and double pass Aluminum AA6061 friction stir weld joints

    NASA Astrophysics Data System (ADS)

    Othman, N. H.; Shah, L. H.; Ishak, M.

    2015-12-01

    This study focuses on the effect of single pass (SP), double sided pass (DSP) and normal double pass (NDP) method on friction stir welding of aluminum AA6061. Two pieces of AA6061 alloy with thickness of 6 mm were friction stir welded by using conventional milling machine. The rotational speeds that were used in this study were 800 rpm, 1000 rpm and 1200 rpm, respectively. The welding speed is fixed to 100 mm/min. Microstructure observation of welded area was studied by using optical microscope. Tensile test and Vickers hardness test were used to evaluate the mechanical properties of this specimen. Mechanical property analysis results indicate that at low rotational speeds, defects such as surface lack of fill and tunneling in the welded area can be observed. Vickers hardness of specimens however did not vary much when rotational speed is varied. Welded specimens using single pass method shows higher tensile strength and hardness value compared to both double pass methods up to 180.61 MPa. Moreover, DSP showed better tensile test and hardness test compared to NDP method. The optimum parameters were found to be single pass method with 1200 rpm of rotational speed. Therefore economically sound to only perform SP method to obtain maximum tensile strength for AA6061 FSW with thickness of 6 mm.

  17. Competition in decentralized electricity markets: Three papers on electricity auctions

    NASA Astrophysics Data System (ADS)

    Harbord, David William Cameron

    This thesis consists of three self-contained papers on the analysis of electricity auctions written over a period of twelve years. The first paper models price competition in a decentralized wholesale market for electricity as a first-price, sealed-bid, multi-unit auction. In both the pure and mixed-strategy equilibria of the model, above marginal cost pricing and inefficient despatch of generating units occur. An alternative regulatory pricing rule is considered and it is shown that offering to supply at marginal cost can be induced as a dominant strategy for all firms. The second paper analyses strategic interaction between long-term contracts and price competition in the British electricity wholesale market, and confirms that forward contracts will tend to put downward pressure on spot market prices. A 'strategic commitment' motive for selling forward contracts is also identified: a generator may commit itself to bidding lower prices into the spot market in order to ensure that it will be despatched with its full capacity. The third paper characterizes bidding behavior and market outcomes in uniform and discriminatory electricity auctions. Uniform auctions result in higher average prices than discriminatory auctions, but the ranking in terms of productive efficiency is ambiguous. The comparative effects of other market design features, such as the number of steps in suppliers' bid functions, the duration of bids and the elasticity of demand are analyzed. The paper also clarifies some methodological issues in the analysis of electricity auctions. In particular we show that analogies with continuous share auctions are misplaced so long as firms are restricted to a finite number of bids.

  18. 49 CFR 580.9 - Odometer record retention for auction companies.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ODOMETER DISCLOSURE REQUIREMENTS § 580.9 Odometer record retention for auction companies. Each auction company shall establish and... following records: (a) The name of the most recent owner (other than the auction company); (b) The name...

  19. Using Laboratory Experiments for Policymaking: An Example from the Georgia Irrigation Reduction Auction

    ERIC Educational Resources Information Center

    Cummings, Ronald G.; Holt, Charles A.; Laury, Susan K.

    2004-01-01

    In recent years, interest has been growing in policy applications of different auction systems. This paper reports a series of experiments that were used to design and implement an auction in a unique policymaking environment. In April 2000, the Georgia legislature passed a law that mandated that the state hold an auction in drought years to pay…

  20. Non-double-couple mechanisms of microearthquakes induced by hydraulic fracturing

    NASA Astrophysics Data System (ADS)

    Šílený, Jan; Hill, David P.; Eisner, Leo; Cornet, Francois H.

    2009-08-01

    We have inverted polarity and amplitude information of representative microearthquakes to investigate source mechanisms of seismicity induced by hydraulic fracturing in the Carthage Cotton Valley, east Texas, gas field. With vertical arrays of four and eight three-component geophones in two monitoring wells, respectively, we were able to reliably determine source mechanisms of the strongest events with the best signal-to-noise ratio. Our analysis indicates predominantly non-double-couple source mechanisms with positive volumetric component consistent with opening cracks oriented close to expected hydraulic fracture orientation. Our observations suggest the induced events are directly the result of opening cracks by fluid injection, in contrast to many previous studies where the seismicity is interpreted to be primarily shearing caused by pore pressure diffusion into the surrounding rock or associated with shear stresses created at the hydraulic fracture tip.

  1. Non-double-couple mechanisms of microearthquakes induced by hydraulic fracturing

    USGS Publications Warehouse

    Sileny, J.; Hill, D.P.; Eisner, L.; Cornet, F.H.

    2009-01-01

    We have inverted polarity and amplitude information of representative microearthquakes to investigate source mechanisms of seismicity induced by hydraulic fracturing in the Carthage Cotton Valley, east Texas, gas field. With vertical arrays of four and eight three-component geophones in two monitoring wells, respectively, we were able to reliably determine source mechanisms of the strongest events with the best signal-to-noise ratio. Our analysis indicates predominantly non-double-couple source mechanisms with positive volumetric component consistent with opening cracks oriented close to expected hydraulic fracture orientation. Our observations suggest the induced events are directly the result of opening cracks by fluid injection, in contrast to many previous studies where the seismicity is interpreted to be primarily shearing caused by pore pressure diffusion into the surrounding rock or associated with shear stresses created at the hydraulic fracture tip. Copyright 2009 by the American Geophysical Union.

  2. Disentangling the various Mechanisms of neutrinoless double beta decay to extract the neutrino mass

    SciTech Connect

    Vergados, J. D.

    2011-12-16

    It is well known that there exist many mechanisms that may contribute to neutrinoless double beta decay. By exploiting the fact that the associated nuclear matrix elements are target dependent we show that, given definite experimental results on a sufficient number of targets, one can determine or sufficiently constrain all lepton violating parameters including the mass term. As a specific example we show that, given the observation of the 0{nu}{beta}{beta}-decay in three different nuclei, e.g. {sup 76}Ge, {sup 100}Mo and {sup 130}Te, and assuming just three active lepton number violating parameters, e.g. light and heavy neutrino mass mechanisms in left handed currents as well as R-parity breaking SUSY mechanism, one may determine all lepton violating parameters, provided that they are relatively real.

  3. Mechanisms governing the interfacial delamination of thermal barrier coating system with double ceramic layers

    NASA Astrophysics Data System (ADS)

    Xu, Rong; Fan, Xueling; Wang, T. J.

    2016-05-01

    A systematic study of factors affecting the interfacial delamination of thermal barrier coating system (TBCs) with double ceramic layers (DCL) is presented. Crack driving forces for delaminations at two weak interfaces are examined. The results show that a thicker outermost ceramic layer can induce dramatic increase in crack driving force and make the interface between two ceramic coatings become more prone to delamination. The behavior is shown to be more prominent in TBCs with stiffer outmost coating. The thickness ratio of two ceramic layers is an important parameter for controlling the failure mechanisms and determining the lifetime of DCL TBCs under inservice condition. By accounting for the influences of thickness ratio of two ceramic layers and interfacial fracture toughnesses of two involved interfaces, the fracture mechanism map of DCL TBCs has been constructed, in which different failure mechanisms are identified. The results quanlitatively agree with the aviliable experimental data.

  4. Bolted Double-Lap Composite Joints Under Mechanical and Thermal Loading

    NASA Technical Reports Server (NTRS)

    Kradinov, V.; Barut, A.; Madenci, E.; Walker, Sandra P. (Technical Monitor)

    2000-01-01

    This study concerns the determination of the contact stresses and contact region around bolt holes and the bolt load distribution in single- and double-lap joints of composite laminates with arbitrarily located bolts under general mechanical loading conditions and uniform temperature change. The unknown contact stress distribution and contact region between the bolt and laminates and the interaction among the bolts require the bolt load distribution, as well as the contact stresses, to be as part of the solution. The present method is based on the complex potential theory and the variational formulation in order to account for bolt stiffness, bolt-hole clearance, and finite geometry of the composite laminates.

  5. 75 FR 21627 - Auction of Lower and Upper Paging Bands Licenses Rescheduled for June 15, 2010; Status of Short...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-26

    ... and upper paging bands spectrum. This auction, which is designated as Auction 87, was initially... COMMISSION Auction of Lower and Upper Paging Bands Licenses Rescheduled for June 15, 2010; Status of Short...,603 licenses for lower and upper paging bands designated Auction 87. DATES: Upfront payments are...

  6. Essays on applied auction problems in electric generation and in neighboring jurisdictions

    SciTech Connect

    Eastman-Perl, K.A.

    1993-01-01

    This work consists of three essays. The first essay, [open quotes]Contract Selection and Performance in Competitive Bidding for Electric Generation,[close quotes], studies the new practice of competitive bidding among third parties to supply utilities with electric generating capacity. The other two essays, entitled [open quotes]First Price Auctions in Neighboring Jurisdictions,[close quotes] and [open quotes]Second Price Auctions in Neighboring Jurisdictions,[close quotes] study the general problem of auctions when there are several auctioneers that can observe each other and can use information from these observations strategically. The first essay notes that competitive bidding programs for electric generation are really auctions of long-term contracts between utility and third parties. Bids and contracts from Maine were studied. Since Maine has a wealth of alternative fuels, such as wood and hydroelectric, the applicability of this study is limited to states with significant alternative fuel resources. The second and third essays consider auctions in neighboring jurisdictions. One concerns first-price auctions (low bid, wins, and is paid its bid), and the other concerns second-price auctions (low bid wins, and is paid the second lowest bid). One town initially holds an auction, the results of which are public information. Another town can use this public information to negotiate with the winner of the initial auction. Firms always bid higher in an initial first-price auction than they would if a neighboring town were not present. In equilibrium, firms are no worse off than they would be if both towns acted independently, and the negotiating town benefits at the expense of the town initially auctioning. In second-price auctions, the incentive compatibility property is preserved if relatively lower cost firms bid in the initial auction. The town initially conducting the auction is unaffected, and the negotiating town benefits at the firm's expense.

  7. Multi-unit auctions with budget-constrained bidders

    NASA Astrophysics Data System (ADS)

    Ghosh, Gagan Pratap

    In my dissertation, I investigate the effects of budget-constraints in multi-unit auctions. This is done in three parts. First, I analyze a case where all bidders have a common budget constraint. Precisely, I analyze an auction where two units of an object are sold at two simultaneous, sealed bid, first-price auctions, to bidders who have demand for both units. Bidders differ with respect to their valuations for the units. All bidders have an identical budget constraint which binds their ability to spend in the auction. I show that if valuation distribution is atom-less, then their does not exist any symmetric equilibrium in this auction game. In the second and third parts of my thesis, I analyze the sale of licenses for the right to drill for oil and natural gas in the Outer Continental Shelf (OCS) of the United States. These sales are conducted using simultaneous sealed-bid first-price auctions for multiple licenses, each representing a specific area (called a tract). Using aspects of observed bidding-behavior, I first make a prima facie case that bidders are budget-constrained in these auctions. In order to formalize this argument, I develop a simple extension of the standard model (where bidders differ in their valuations for the objects) by incorporating (random) budgets for the bidders. The auction-game then has a two-dimensional set of types for each player. I study the theoretical properties of this auction, assuming for simplicity that two units are being sold. I show that this game has an equilibrium in pure strategies that is symmetric with respect to the players and with respect to the units. The strategies are essentially pure in the sense that each bidder-type has a unique split (up to a permutation) of his budget between the two auctions. I then characterize the equilibrium in terms of the bid-distribution and iso-bid curves in the value-budget space. I derive various qualitative features of this equilibrium, among which are: (1) under mild

  8. Double strand binding – single strand incision mechanism for human flap endonuclease: implications for the superfamily

    PubMed Central

    Tsutakawa, Susan E.; Tainer, John A.

    2012-01-01

    Detailed structural, mutational, and biochemical analyses of human FEN1/DNA complexes have revealed the mechanism for recognition of 5′ flaps formed during lagging strand replication and DNA repair. FEN1 processes 5′ flaps through a previously unknown, but structurally elegant double-stranded (ds) recognition/single stranded (ss) incision mechanism that both selects for 5′ flaps and selects against ss DNA or RNA, intact dsDNA, and 3′ flaps. Two major DNA binding interfaces, including a K+ bridge between the DNA and the H2TH motif, are spaced one helical turn apart and together select for substrates with dsDNA. A conserved helical gateway and a helical cap protects the two-metal active site and selects for ss flaps with free termini. Structures of substrate and product reveal an unusual step between binding substrate and incision that involves a double base unpairing with incision occurring in the resulting unpaired DNA or RNA. Ordering of the active site requires a disorder-to-order transition induced by binding of an unpaired 3′ flap, which ensures that the product is ligatable. Comparison with FEN superfamily members, including XPG, EXO1, and GEN1, identifies superfamily motifs such as the helical gateway that select for ss-dsDNA junctions and provides key biological insights into nuclease specificity and regulation. PMID:22244820

  9. Non-double-couple earthquake mechanisms at the Hengill-Grensdalur volcanic complex, southwest Iceland

    USGS Publications Warehouse

    Julian, B.R.; Miller, A.D.; Foulger, G.R.

    1997-01-01

    The Hengill-Grensdalur area in Iceland generates frequent small non-double-couple earthquakes with explosive volumetric components. We collected high quality three-component digital recordings of 4,000 earthquakes on a purpose-designed, 32-station network in 1991, and determined focal mechanisms for 100 of the best-recorded earthquakes by inverting amplitude ratios. Many of the mechanisms are consistent, within the errors, with simultaneous shear and tensile faulting, with tensile faults parallel to the local spreading ridge, and shear faulting similar to that in the South Iceland transform-fault zone. Some events cannot be explained by this model, however, and require other processes, such as crack closing and partial compensation of tensile cracks by fluid flow.

  10. Molecular Dynamics Study of Double-Walled Carbon Nanotubes for Nano-Mechanical Manipulation

    NASA Astrophysics Data System (ADS)

    Kimoto, Yoshihisa; Mori, Hideki; Mikami, Tomohito; Akita, Seiji; Nakayama, Yoshikazu; Higashi, Kenji; Hirai, Yoshihiko

    2005-04-01

    Double-walled carbon nanotubes (DWNTs) are expected to be useful as elements in nano-mechanical systems such as nanobearings and nanosliders. A molecular dynamics simulation is carried out to estimate the relative motion between the inner and outer tubes. The force required to pull the inner tube out of the outer tube is evaluated quantitatively by pulling the inner tube under a constant velocity for DWNTs with various inter-tube spacings and chiralities. When the inner tube is pulled under smaller constant force, the inner tube vibrates inside the outer tube without being pulled out, and an energetics is applied to explain the critical force and vibrational amplitude. The constant force induces not only vibration along the tube axis but also rotation around the tube axis, which indicates the possibility of creating a slider crank mechanism using a DWNT.

  11. A Gravitational Double-scattering Mechanism for Generating High-velocity Objects during Halo Mergers

    NASA Astrophysics Data System (ADS)

    Samsing, Johan

    2015-02-01

    We present a dynamical model that describes how halo particles can receive a significant energy kick from the merger between their own host halo and a target halo. This could provide a possible explanation for some high-velocity objects, including extended systems like globular clusters (GCs). In the model we especially introduce a double-scattering mechanism, where a halo particle receives a significant part of its total energy kick by first undergoing a gravitational deflection by the target halo and subsequently by its original host halo. This generates an energy kick that is due to the relative velocity between the halos during the deflections. We derive analytically the total kick energy of the particle, which is composed of energy from the double-scattering mechanism and tidal fields, as a function of its position in its original host halo just before merger. In the case of a 1:10 merger, we find that the presented mechanisms can easily generate particles with a velocity approximately two times the virial velocity of the target halo. This motivates us to suggest that the high velocity of the recently discovered GC HVGC-1 can be explained by a head-on halo merger. Finally, we illustrate the orbital evolution of high-velocity particles outside the virial sphere of the target halo by solving the equation of motion in an expanding universe. We find a sweet spot around a scale factor of 0.3-0.5 for ejecting particles into large orbits, which can easily reach beyond approximately five virial radii.

  12. A GRAVITATIONAL DOUBLE-SCATTERING MECHANISM FOR GENERATING HIGH-VELOCITY OBJECTS DURING HALO MERGERS

    SciTech Connect

    Samsing, Johan

    2015-02-01

    We present a dynamical model that describes how halo particles can receive a significant energy kick from the merger between their own host halo and a target halo. This could provide a possible explanation for some high-velocity objects, including extended systems like globular clusters (GCs). In the model we especially introduce a double-scattering mechanism, where a halo particle receives a significant part of its total energy kick by first undergoing a gravitational deflection by the target halo and subsequently by its original host halo. This generates an energy kick that is due to the relative velocity between the halos during the deflections. We derive analytically the total kick energy of the particle, which is composed of energy from the double-scattering mechanism and tidal fields, as a function of its position in its original host halo just before merger. In the case of a 1:10 merger, we find that the presented mechanisms can easily generate particles with a velocity approximately two times the virial velocity of the target halo. This motivates us to suggest that the high velocity of the recently discovered GC HVGC-1 can be explained by a head-on halo merger. Finally, we illustrate the orbital evolution of high-velocity particles outside the virial sphere of the target halo by solving the equation of motion in an expanding universe. We find a sweet spot around a scale factor of 0.3-0.5 for ejecting particles into large orbits, which can easily reach beyond approximately five virial radii.

  13. Determination of effective mechanical properties of a double-layer beam by means of a nano-electromechanical transducer

    SciTech Connect

    Hocke, Fredrik; Pernpeintner, Matthias; Gross, Rudolf; Zhou, Xiaoqing; Kippenberg, Tobias J.; Schliesser, Albert; Huebl, Hans

    2014-09-29

    We investigate the mechanical properties of a doubly clamped, double-layer nanobeam embedded into an electromechanical system. The nanobeam consists of a highly pre-stressed silicon nitride and a superconducting niobium layer. By measuring the mechanical displacement spectral density both in the linear and the nonlinear Duffing regime, we determine the pre-stress and the effective Young's modulus of the nanobeam. An analytical double-layer model quantitatively corroborates the measured values. This suggests that this model can be used to design mechanical multilayer systems for electro- and optomechanical devices, including materials controllable by external parameters such as piezoelectric, magnetostrictive, or in more general multiferroic materials.

  14. Determination of effective mechanical properties of a double-layer beam by means of a nano-electromechanical transducer

    NASA Astrophysics Data System (ADS)

    Hocke, Fredrik; Pernpeintner, Matthias; Zhou, Xiaoqing; Schliesser, Albert; Kippenberg, Tobias J.; Huebl, Hans; Gross, Rudolf

    2014-09-01

    We investigate the mechanical properties of a doubly clamped, double-layer nanobeam embedded into an electromechanical system. The nanobeam consists of a highly pre-stressed silicon nitride and a superconducting niobium layer. By measuring the mechanical displacement spectral density both in the linear and the nonlinear Duffing regime, we determine the pre-stress and the effective Young's modulus of the nanobeam. An analytical double-layer model quantitatively corroborates the measured values. This suggests that this model can be used to design mechanical multilayer systems for electro- and optomechanical devices, including materials controllable by external parameters such as piezoelectric, magnetostrictive, or in more general multiferroic materials.

  15. Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model

    PubMed Central

    Shen, Dongkai; Zhang, Qian

    2016-01-01

    In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP) controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics.

  16. Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model

    PubMed Central

    Shen, Dongkai; Zhang, Qian

    2016-01-01

    In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP) controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics. PMID:27660646

  17. 29 CFR 780.617 - Adjunct livestock auction operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption Requirements... referred to in section 13(b)(13) are those engaged in by the farmer “as an adjunct” to the raising of... claim exemption under section 13(b)(13). To qualify under the exemption provision, the...

  18. 29 CFR 780.617 - Adjunct livestock auction operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Employment in Agriculture and Livestock Auction Operations Under the Section 13(b)(13) Exemption Requirements... referred to in section 13(b)(13) are those engaged in by the farmer “as an adjunct” to the raising of... claim exemption under section 13(b)(13). To qualify under the exemption provision, the...

  19. Understanding Persuasive Online Sales Messages from eBay Auctions

    ERIC Educational Resources Information Center

    White, Barbara Jo; Clapper, Danial; Noel, Rita; Fortier, Jenny; Grabolosa, Pierre

    2007-01-01

    Online auctions are dominated by eBay, which started bringing together buyers and sellers in 1995. eBay product listings can easily be used in business communication courses to better understand online sales messages. One great advantage is that the vast majority of nearly 15 million listings a day are written and assembled by everyday consumers…

  20. Making Marketing Principles Tangible: Online Auctions as Living Case Studies

    ERIC Educational Resources Information Center

    Wood, Charles M.; Suter, Tracy A.

    2004-01-01

    This article presents an effective course supplement for Principles of Marketing classes. An experiential project involving online auctions is offered to instructors seeking to create a more participatory student environment and an interactive teaching style. A number of learning points are illustrated that allow instructors to use an auction…

  1. Empirical regularities of opening call auction in Chinese stock market

    NASA Astrophysics Data System (ADS)

    Gu, Gao-Feng; Ren, Fei; Ni, Xiao-Hui; Chen, Wei; Zhou, Wei-Xing

    2010-01-01

    We study the statistical regularities of an opening call auction using the ultra-high-frequency data of 22 liquid stocks traded on the Shenzhen Stock Exchange in 2003. The distribution of the relative price, defined as the relative difference between the order price in the opening call auction and the closing price on the last trading day, is asymmetric and that the distribution displays a sharp peak at the zero relative price and a relatively wide peak at the negative relative price. The detrended fluctuation analysis (DFA) method is adopted to investigate the long-term memory of relative order prices. We further study the statistical regularities of order sizes in the opening call auction, and observe a phenomenon of number preference, known as order size clustering. The probability density function (PDF) of order sizes could be well fitted by a q-Gamma function, and the long-term memory also exists in order sizes. In addition, both the average volume and the average number of orders decrease exponentially with the price level away from the best bid or ask price level in the limit-order book (LOB) established immediately after the opening call auction, and a price clustering phenomenon is observed.

  2. Teaching Auction Strategy Using Experiments Administered Via the Internet

    ERIC Educational Resources Information Center

    Asker, John; Grosskopf, Brit; McKinney, C. Nicholas; Niederle, Muriel; Roth, Alvin E.; Weizsacker, Georg

    2004-01-01

    The authors present an experimental design used to teach concepts in the economics of auctions and implications for e-Business procurement. The experiment is easily administered and can be adapted to many different treatments. The chief innovation is that it does not require the use of a lab or class time. Instead, the design can be implemented on…

  3. 15. Detail view of the original auction podium in the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Detail view of the original auction podium in the 1937 arena (main section), with the west bleachers at the left, the north bleachers at the right, and the monitor roof structure, supported by posts, above; looking northwest - Ewing Livestock Market, South side of First Avenue North, 500 feet west of Route 724, Ewing, Lee County, VA

  4. 41 CFR 102-38.95 - What is an auction?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false What is an auction? 102-38.95 Section 102-38.95 Public Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION PERSONAL PROPERTY 38-SALE OF PERSONAL...

  5. Structural Basis for Elastic Mechanical Properties of the DNA Double Helix

    PubMed Central

    Kim, Young-Joo; Kim, Do-Nyun

    2016-01-01

    In this article, we investigate the principal structural features of the DNA double helix and their effects on its elastic mechanical properties. We develop, in the pursuit of this purpose, a helical continuum model consisting of a soft helical core and two stiff ribbons wrapping around it. The proposed model can reproduce the negative twist-stretch coupling of the helix successfully as well as its global stretching, bending, and torsional rigidities measured experimentally. Our parametric study of the model using the finite element method further reveals that the stiffness of phosphate backbones is a crucial factor for the counterintuitive overwinding behavior of the duplex and its extraordinarily high torsional rigidity, the major-minor grooves augment the twist-stretch coupling, and the change of the helicity might be responsible for the transition from a negative to a positive twist-stretching coupling when a tensile force is applied to the duplex. PMID:27055239

  6. [Plasma temperature calculation and coupling mechanism analysis of laser-double wire hybrid welding].

    PubMed

    Zheng, Kai; Li, Huan; Yang, Li-Jun; Gu, Xiao-Yan; Gao, Ying

    2013-04-01

    The plasma radiation of laser-double wire hybrid welding was collected by using fiber spectrometer, the coupling mechanism of arc with laser was studied through high-speed photography during welding process, and the temperature of hybrid plasma was calculated by using the method of Boltzmann plot. The results indicated that with laser hybrid, luminance was enhanced; radiation intensity became stronger; arc was attracted to the laser point; cross section contracted and arc was more stable. The laser power, welding current and arc-arc distance are important factors that have great influence on electron temperature. Increase in the laser power, amplification of welding current and reduction of arc-arc distance can all result in the rise of temperature. PMID:23841392

  7. Double-ionization mechanisms of the argon dimer in intense laser fields

    SciTech Connect

    Ulrich, B.; Vredenborg, A.; Malakzadeh, A.; Meckel, M.; Cole, K.; Jahnke, T.; Doerner, R.; Smolarski, M.; Chang, Z.

    2010-07-15

    We have measured the two-site double ionization of argon dimers by ultrashort laser pulses leading to fragmentation into two singly charged argon ions. Contrary to the expectations from a pure Coulomb explosion following rapid removal of one electron from each of the atoms, we find three distinct peaks in the kinetic energy release (KER) distribution. By measuring the angular distribution of the fragment ions and the vector momentum of one of the emitted electrons for circular and linear laser polarization, we are able to unravel the ionization mechanisms leading to the three features in the KER. The most abundant one results from tunnel ionization at one site followed by charge-enhanced tunnel ionization of the second atom. The second mechanism, which leads to a higher KER we identify as sequential tunnel ionization of both atoms accompanied by excitation. The third mechanism is present with linearly polarized light only. It is most likely a frustrated triple ionization, where the third electron does not escape but is trapped in a Rydberg state.

  8. Superior mechanical properties of double-network hydrogels reinforced by carbon nanotubes without organic modification.

    PubMed

    Dong, Weifu; Huang, Chiguang; Wang, Yang; Sun, Yujie; Ma, Piming; Chen, Mingqing

    2013-01-01

    A facile method is developed to fabricate nanocomposite double-network (DN) gels with excellent mechanical properties, which do not fracture upon loading up to 78 MPa and a strain above 0.98, by compositing of carbon nanotubes (CNTs) without organic modification. Investigations of swelling behaviors, and compressive and tensile properties indicate that equilibrium swelling ratio, compressive modulus and stress, fracture stress, Young's modulus, and yield stress are significantly improved in the presence of CNTs. Scanning electron microscopy (SEM) reveals that the pore size of nanocomposite DN gels is decreased and some embedded micro-network structures are observed on the fracture surface in comparison to DN gels without CNTs, which leads to the enhancement of mechanical properties. The compressive loading-unloading behaviors show that the area of hysteresis loop, dissipated energy, for the first compressive cycle, increases with addition of CNTs, which is much higher than that for the successive cycles. Furthermore, the energy dissipation mechanism, similar to the Mullins effect observed in filled rubbers, is demonstrated for better understanding the nanocomposite DN polymer gels with CNTs. PMID:24232456

  9. Classical and quantum-mechanical treatments of nonsequential double ionization with few-cycle laser pulses

    NASA Astrophysics Data System (ADS)

    Figueira de Morisson Faria, C.; Liu, X.; Sanpera, A.; Lewenstein, M.

    2004-10-01

    We address nonsequential double ionization induced by strong, linearly polarized laser fields of only a few cycles, considering a physical mechanism in which the second electron is dislodged by the inelastic collision of the first electron with its parent ion. The problem is treated classically, using an ensemble model, and quantum mechanically, within the strong-field and uniform saddle-point approximations. In the latter case, the results are interpreted in terms of “quantum orbits,” which can be related to the trajectories of a classical electron in an electric field. We obtain highly asymmetric electron momentum distributions, which strongly depend on the absolute phase, i.e., on the phase difference between the pulse envelope and its carrier frequency. Around a particular value of this parameter, the distributions shift from the region of positive to that of negative momenta, or vice versa, in a radical fashion. This behavior is investigated in detail for several driving-field parameters, and provides a very efficient method for measuring the absolute phase. Both models yield very similar distributions, which share the same physical explanation. There exist, however, minor discrepancies due to the fact that, beyond the region for which electron-impact ionization is classically allowed, the yields from the quantum-mechanical computation decay exponentially, whereas their classical counterparts vanish.

  10. Insect-like flapping wing mechanism based on a double spherical Scotch yoke

    PubMed Central

    Galiński, Cezary; Żbikowski, Rafał

    2005-01-01

    We describe the rationale, concept, design and implementation of a fixed-motion (non-adjustable) mechanism for insect-like flapping wing micro air vehicles in hover, inspired by two-winged flies (Diptera). This spatial (as opposed to planar) mechanism is based on the novel idea of a double spherical Scotch yoke. The mechanism was constructed for two main purposes: (i) as a test bed for aeromechanical research on hover in flapping flight, and (ii) as a precursor design for a future flapping wing micro air vehicle. Insects fly by oscillating (plunging) and rotating (pitching) their wings through large angles, while sweeping them forwards and backwards. During this motion the wing tip approximately traces a ‘figure-of-eight’ or a ‘banana’ and the wing changes the angle of attack (pitching) significantly. The kinematic and aerodynamic data from free-flying insects are sparse and uncertain, and it is not clear what aerodynamic consequences different wing motions have. Since acquiring the necessary kinematic and dynamic data from biological experiments remains a challenge, a synthetic, controlled study of insect-like flapping is not only of engineering value, but also of biological relevance. Micro air vehicles are defined as flying vehicles approximately 150 mm in size (hand-held), weighing 50–100 g, and are developed to reconnoitre in confined spaces (inside buildings, tunnels, etc.). For this application, insect-like flapping wings are an attractive solution and hence the need to realize the functionality of insect flight by engineering means. Since the semi-span of the insect wing is constant, the kinematics are spatial; in fact, an approximate figure-of-eight/banana is traced on a sphere. Hence a natural mechanism implementing such kinematics should be (i) spherical and (ii) generate mathematically convenient curves expressing the figure-of-eight/banana shape. The double spherical Scotch yoke design has property (i) by definition and achieves (ii) by

  11. A three-dimensional statistical mechanical model of folding double-stranded chain molecules

    NASA Astrophysics Data System (ADS)

    Zhang, Wenbing; Chen, Shi-Jie

    2001-05-01

    Based on a graphical representation of intrachain contacts, we have developed a new three-dimensional model for the statistical mechanics of double-stranded chain molecules. The theory has been tested and validated for the cubic lattice chain conformations. The statistical mechanical model can be applied to the equilibrium folding thermodynamics of a large class of chain molecules, including protein β-hairpin conformations and RNA secondary structures. The application of a previously developed two-dimensional model to RNA secondary structure folding thermodynamics generally overestimates the breadth of the melting curves [S-J. Chen and K. A. Dill, Proc. Natl. Acad. Sci. U.S.A. 97, 646 (2000)], suggesting an underestimation for the sharpness of the conformational transitions. In this work, we show that the new three-dimensional model gives much sharper melting curves than the two-dimensional model. We believe that the new three-dimensional model may give much improved predictions for the thermodynamic properties of RNA conformational changes than the previous two-dimensional model.

  12. Telomere Dysfunction Triggers Palindrome Formation Independently of Double-Strand Break Repair Mechanisms

    PubMed Central

    Raykov, Vasil; Marvin, Marcus E.; Louis, Edward J.; Maringele, Laura

    2016-01-01

    Inverted chromosome duplications or palindromes are linked with genetic disorders and malignant transformation. They are considered by-products of DNA double-strand break (DSB) repair: the homologous recombination (HR) and the nonhomologous end joining (NHEJ). Palindromes near chromosome ends are often triggered by telomere losses. An important question is to what extent their formation depends upon DSB repair mechanisms. Here we addressed this question using yeast genetics and comparative genomic hybridization. We induced palindrome formation by passaging cells lacking any form of telomere maintenance (telomerase and telomere recombination). Surprisingly, we found that DNA ligase 4, essential for NHEJ, did not make a significant contribution to palindrome formation induced by telomere losses. Moreover RAD51, important for certain HR-derived mechanisms, had little effect. Furthermore RAD52, which is essential for HR in yeast, appeared to decrease the number of palindromes in cells proliferating without telomeres. This study also uncovered an important role for Rev3 and Rev7 (but not for Pol32) subunits of polymerase ζ in the survival of cells undergoing telomere losses and forming palindromes. We propose a model called short-inverted repeat-induced synthesis in which DNA synthesis, rather than DSB repair, drives the inverted duplication triggered by telomere dysfunction. PMID:27334270

  13. Failure mechanisms of concrete slab-soil double-layer structure subjected to underground explosion

    NASA Astrophysics Data System (ADS)

    Tan, Z.; Zhang, W.; Cho, C.; Han, X.

    2014-09-01

    The failure mechanism of a concrete slab-soil double-layer structure subjected to an underground explosion was investigated by experimental and numerical methods in this paper. Two underground explosion depths of 150 and 350 mm were tested. The typical failure modes such as the conoid spall of concrete, the bulge of the concrete slab and the cavity in the soil were obtained experimentally. Numerical simulations of the experiments were performed using a hydrodynamic code to analyze the effects of both the stress wave and the expansion of the blast products. Based on the experimental and numerical results, the effects of explosive depth, blast wave front and expansion of the blast products on the failure modes and failure mechanisms were discussed. The underground explosion process at different explosion depths was also analyzed. The results show that attenuation of the stress wave in the soil is significant. The blast wave front and the expansion of the blast products play different roles at different explosion depths. At the explosion depth of 150 mm, the failure mode is mainly caused by a point load induced by the blast wave front, whereas at the depth of 350 mm a sphere-shaped load resulting from the expansion of the blast products is a key factor for failure.

  14. Mechanisms and Consequences of Double-Strand DNA Break Formation in Chromatin.

    PubMed

    Cannan, Wendy J; Pederson, David S

    2016-01-01

    All organisms suffer double-strand breaks (DSBs) in their DNA as a result of exposure to ionizing radiation. DSBs can also form when replication forks encounter DNA lesions or repair intermediates. The processing and repair of DSBs can lead to mutations, loss of heterozygosity, and chromosome rearrangements that result in cell death or cancer. The most common pathway used to repair DSBs in metazoans (non-homologous DNA end joining) is more commonly mutagenic than the alternative pathway (homologous recombination mediated repair). Thus, factors that influence the choice of pathways used DSB repair can affect an individual's mutation burden and risk of cancer. This review describes radiological, chemical, and biological mechanisms that generate DSBs, and discusses the impact of such variables as DSB etiology, cell type, cell cycle, and chromatin structure on the yield, distribution, and processing of DSBs. The final section focuses on nucleosome-specific mechanisms that influence DSB production, and the possible relationship between higher order chromosome coiling and chromosome shattering (chromothripsis). PMID:26040249

  15. Suppressing the mechanical quadrature error of a quartz double-H gyroscope through laser trimming

    NASA Astrophysics Data System (ADS)

    Zhao, Ke; Feng, Li-Hui; Wang, Qian-Qian; Liu, Ming-Zhi; Wang, Ben-Guo; Cui, Fang; Sun, Yu-Nan

    2013-11-01

    In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppress this error at quartz level. The trimming law is obtained through the finite element method (FEM). A femtosecond laser processing system is used to trim the gold balancing masses on the beams, and experimental results are basically consistent with the simulated ones. The mechanical quadrature error is suppressed by 96%, from 26.3° s-1 to 1.1° s-1. Nonlinearity changes from 1.48% to 0.30%, angular random walk (ARW) is reduced from 2.19° h-1/2 to 1.42° h-1/2, and bias instability is improved by a factor of 7.7, from 197.6° h-1 to 25.4° h-1.

  16. Design and Promotion Strategy of Marketing Platform of Aquatic Auction based on Internet

    NASA Astrophysics Data System (ADS)

    Peng, Jianliang

    For the online trade and promotion of aquatic products and related materials through the network between supply and demand, the design content and effective promotional strategies of aquatic auctions online marketing platform is proposed in this paper. Design elements involve the location of customer service, the basic function of the platform including the purchase of general orders, online auctions, information dissemination, and recommendation of fine products, human services, and payment preferences. Based on network and mobile e-commerce transaction support, the auction platform makes the transaction of aquatic products well in advance. The results are important practical value for the design and application of online marketing platform of aquatic auction.

  17. Mechanisms of DNA Packaging by Large Double-Stranded DNA Viruses.

    PubMed

    Rao, Venigalla B; Feiss, Michael

    2015-11-01

    Translocation of viral double-stranded DNA (dsDNA) into the icosahedral prohead shell is catalyzed by TerL, a motor protein that has ATPase, endonuclease, and translocase activities. TerL, following endonucleolytic cleavage of immature viral DNA concatemer recognized by TerS, assembles into a pentameric ring motor on the prohead's portal vertex and uses ATP hydrolysis energy for DNA translocation. TerL's N-terminal ATPase is connected by a hinge to the C-terminal endonuclease. Inchworm models propose that modest domain motions accompanying ATP hydrolysis are amplified, through changes in electrostatic interactions, into larger movements of the C-terminal domain bound to DNA. In phage ϕ29, four of the five TerL subunits sequentially hydrolyze ATP, each powering translocation of 2.5 bp. After one viral genome is encapsidated, the internal pressure signals termination of packaging and ejection of the motor. Current focus is on the structures of packaging complexes and the dynamics of TerL during DNA packaging, endonuclease regulation, and motor mechanics. PMID:26958920

  18. Methotrexatum intercalated layered double hydroxides: statistical design, mechanism explore and bioassay study.

    PubMed

    Wang, Xiao-Feng; Liu, Su-Qing; Li, Shu-Ping

    2015-04-01

    A series of methotrexatum intercalated layered double hydroxide (MTX/LDH for short) hybrids have been synthesized by a mechanochemical-hydrothermal method, the statistical experiments are planned and conducted to find out the critical factor influencing the physicochemical properties. Four variables, i.e., addition of NaOH solution, grinding duration, hydrothermal temperature and time, are chosen to play as the examined factors in the orthogonal design. Furthermore, three respective levels, i.e., high, medium and low levels, are conducted in the design. The resulting hybrids are then characterized by X-ray diffraction (XRD) patterns, transmission electron microscope (TEM) graphs and Zeta potentials. XRD diffractions indicate that MTX anions have been successfully intercalated into LDH interlayers and the amount of NaOH solution can change the gallery height greatly. The information from TEM graphs and Zeta potentials state that the increase of alkali solution gives rise to regular morphology and the increase of Zeta potentials. As a result of the statistical analysis, addition of alkali solution is the major factor affecting the morphology and drug-loading capacity. At last, the mechanism of particle growth is explored emphatically, and the anticancer efficacy of some MTX/LDH hybrids is estimated by MTT assay on A549 cells as well.

  19. Mechanisms of DNA Packaging by Large Double-Stranded DNA Viruses

    PubMed Central

    Rao, Venigalla B.; Feiss, Michael

    2016-01-01

    Translocation of viral double-stranded DNA (dsDNA) into the icosahedral prohead shell is catalyzed by TerL, a motor protein that has ATPase, endonuclease, and translocase activities. TerL, following endonucleolytic cleavage of immature viral DNA concatemer recognized by TerS, assembles into a pentameric ring motor on the prohead’s portal vertex and uses ATP hydrolysis energy for DNA translocation. TerL’s N-terminal ATPase is connected by a hinge to the C-terminal endonuclease. Inchworm models propose that modest domain motions accompanying ATP hydrolysis are amplified, through changes in electrostatic interactions, into larger movements of the C-terminal domain bound to DNA. In phage φ29, four of the five TerL subunits sequentially hydrolyze ATP, each powering translocation of 2.5 bp. After one viral genome is encapsidated, the internal pressure signals termination of packaging and ejection of the motor. Current focus is on the structures of packaging complexes and the dynamics of TerL during DNA packaging, endonuclease regulation, and motor mechanics. PMID:26958920

  20. Mechanisms of chemotherapy-induced human ovarian aging: double strand DNA breaks and microvascular compromise.

    PubMed

    Soleimani, Reza; Heytens, Elke; Darzynkiewicz, Zbigniew; Oktay, Kutluk

    2011-08-01

    The mechanism of chemotherapy-induced acceleration of ovarian aging is not fully understood. We used doxorubicin, a widely used cancer chemotherapeutic, in a variety of in vivo xenograft, and in vitro models to investigate the impact of chemotherapy-induced aging on the human ovary. Doxorubicin caused massive double-strand-DNA-breaks in primordial follicles, oocytes, and granulosa cells in a dose dependent fashion as revealed by accumulating γH2AX foci. This damage was associated with apoptotic oocyte death and resulted in the activation of ATM. It appeared that the repair response enabled a minor proportion of oocytes (34.7%) and granulosa cells (12.1%) to survive while the majority succumbed to apoptotic death. Paradoxically, inhibition of ATM by KU-55933 resulted in improved survival, probably via prevention of downstream activation of TAp63α. Furthermore, doxorubicin caused vascular and stromal damage in the human ovary, which might impair ovarian function both pre- and post-menopausally. Chemotherapy-induced premature ovarian aging appears to result from a complex process involving both the germ- and non-germ cell components of the ovary. These effects may have clinical implications in aging both for premenopausal and postmenopausal cancer survivors. PMID:21869459

  1. A single double-strand break system reveals repair dynamics and mechanisms in heterochromatin and euchromatin.

    PubMed

    Janssen, Aniek; Breuer, Gregory A; Brinkman, Eva K; van der Meulen, Annelot I; Borden, Sean V; van Steensel, Bas; Bindra, Ranjit S; LaRocque, Jeannine R; Karpen, Gary H

    2016-07-15

    Repair of DNA double-strand breaks (DSBs) must be properly orchestrated in diverse chromatin regions to maintain genome stability. The choice between two main DSB repair pathways, nonhomologous end-joining (NHEJ) and homologous recombination (HR), is regulated by the cell cycle as well as chromatin context.Pericentromeric heterochromatin forms a distinct nuclear domain that is enriched for repetitive DNA sequences that pose significant challenges for genome stability. Heterochromatic DSBs display specialized temporal and spatial dynamics that differ from euchromatic DSBs. Although HR is thought to be the main pathway used to repair heterochromatic DSBs, direct tests of this hypothesis are lacking. Here, we developed an in vivo single DSB system for both heterochromatic and euchromatic loci in Drosophila melanogaster Live imaging of single DSBs in larval imaginal discs recapitulates the spatio-temporal dynamics observed for irradiation (IR)-induced breaks in cell culture. Importantly, live imaging and sequence analysis of repair products reveal that DSBs in euchromatin and heterochromatin are repaired with similar kinetics, employ both NHEJ and HR, and can use homologous chromosomes as an HR template. This direct analysis reveals important insights into heterochromatin DSB repair in animal tissues and provides a foundation for further explorations of repair mechanisms in different chromatin domains. PMID:27474442

  2. Mechanical behaviour of cross-country ski racing poles during double poling.

    PubMed

    Stöggl, Thomas; Karlöf, Lars

    2013-11-01

    The purpose of this study was to evaluate the behaviour of cross-country ski poles during double poling on a treadmill using three-dimensional kinematics. The results were compared with standard laboratory tests of the pole manufacturers. A total of 18 skiers were analysed at two speeds (85% and 95% of the maximal speed) at grades of 1.5% and 7%. Variables describing cycle characteristics, bending stiffness, bending behaviour, and trajectories of the pole markers were analysed. Triangular-shaped poles demonstrated the greatest stiffness and lowest variability in maximal bending. Softer poles demonstrated greater variability in bending behaviour and lost ground contact at high skiing speeds, which for some skiers resulted in failure to complete high-speed tests. Considerable variations in pole behaviour for similar poles between skiers were observed, which might be attributed to differences in technique, indicating that mechanical properties of the poles did not exclusively determine pole behaviour in the dynamic situation. The greatest magnitude of pole bending was in the middle part of the pole, which differed from the standard static pole analysis of the manufacturer. Increases in grade demonstrated the greatest effect on pole bending. Distinct differences from the pole manufacturers' laboratory measures were apparent, suggesting that basic pole testing might be adapted.

  3. Large displacement behavior of double parallelogram flexure mechanisms with underconstraint eliminators

    DOE PAGES

    Panas, Robert M.

    2016-06-23

    This paper presents a new analytical method for predicting the large displacement behavior of flexural double parallelogram (DP) bearings with underconstraint eliminator (UE) linkages. This closed-form perturbative Euler analysis method is able to – for the first time – directly incorporate the elastomechanics of a discrete UE linkage, which is a hybrid flexure element that is linked to ground as well as both stages on the bearing. The models are used to understand a nested linkage UE design, however the method is extensible to other UE linkages. Design rules and figures-of-merit are extracted from the analysis models, which provide powerfulmore » tools for accelerating the design process. The models, rules and figures-of-merit enable the rapid design of a UE for a desired large displacement behavior, as well as providing a means for determining the limits of UE and DP structures. This will aid in the adoption of UE linkages into DP bearings for precision mechanisms. Models are generated for a nested linkage UE design, and the performance of this DP with UE structure is compared to a DP-only bearing. As a result, the perturbative Euler analysis is shown to match existing theories for DP-only bearings with distributed compliance within ≈2%, and Finite Element Analysis for the DP with UE bearings within an average 10%.« less

  4. Research on the Mechanical Properties of "Z" Type Double-Decker Ball Bearings.

    PubMed

    Yu, Chengtao; Xu, Longxiang; Yu, Xudong

    2014-01-01

    The mechanical model of a "Z" type double-decker ball bearing under the action of radial load is established in this paper on the basis of the Hertz contact theory. According to the security contact angle theory, the influences of inner and outer bearings' internal clearances on the bearing's static load carrying capacity, radial deformation, radial stiffness, and load distribution of balls are analyzed. This model is verified in both stationary and rotational loading experiments. Moreover, the simulation results show that the static load carrying capacity of Z type bearing is smaller than that of either inner bearing or outer bearing that is contributed to compose the Z type bearing. The static load carrying capacity of a Z type bearing reduces with the increase of the inner and outer bearings' internal clearance. These simulation results also indicate that the contact angle of the maximum loaded ball in the outer bearing easily exceeds its security contact angle compared with the inner bearing, which, as the main factor, may cause the Z type bearing to overload and to fail. In this sense, the investigated Z type bearings are unfit to apply to situations with heavy load, high speed, or high precision.

  5. Driving mechanisms of ionic polymer actuators having electric double layer capacitor structures.

    PubMed

    Imaizumi, Satoru; Kato, Yuichi; Kokubo, Hisashi; Watanabe, Masayoshi

    2012-04-26

    Two solid polymer electrolytes, composed of a polyether-segmented polyurethaneurea (PEUU) and either a lithium salt (lithium bis(trifluoromethanesulfonyl)amide: Li[NTf2]) or a nonvolatile ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide: [C2mim][NTf2]), were prepared in order to utilize them as ionic polymer actuators. These salts were preferentially dissolved in the polyether phases. The ionic transport mechanism of the polyethers was discussed in terms of the diffusion coefficients and ionic transference numbers of the incorporated ions, which were estimated by means of pulsed-field gradient spin-echo (PGSE) NMR. There was a distinct difference in the ionic transport properties of each polymer electrolyte owing to the difference in the magnitude of interactions between the cations and the polyether. The anionic diffusion coefficient was much faster than that of the cation in the polyether/Li[NTf2] electrolyte, whereas the cation diffused faster than the anion in the polyether/[C2mim][NTf2] electrolyte. Ionic polymer actuators, which have a solid-state electric-double-layer-capacitor (EDLC) structure, were prepared using these polymer electrolyte membranes and ubiquitous carbon materials such as activated carbon and acetylene black. On the basis of the difference in the motional direction of each actuator against applied voltages, a simple model of the actuation mechanisms was proposed by taking the difference in ionic transport properties into consideration. This model discriminated the behavior of the actuators in terms of the products of transference numbers and ionic volumes. The experimentally observed behavior of the actuators was successfully explained by this model. PMID:22489566

  6. Auctions and alternative procedures for allocating pollution rights

    SciTech Connect

    Lyon, R.M.

    1982-02-01

    This paper considers two different types of auctions which the government could use to sell discharge rights: (1) an auction where rights are sold for a single clearing price, and (2) a special type of discriminating auction that discourages strategic manipulation of bids by individual dischargers. Based on both theoretical and practical considerations, there appears to be a fundamental trade-off between reducing the financial burden of rights purchases and eliminating the incentives for strategic behavior. Very few discharges in either case study would have lower expenses under government sales of rights than under uniform treatment. The simulations also suggest that there may be opportunities for strategic behavior under nonincentive-compatible procedures because of small numbers of dischargers, despite its problems with respect to incentive compatibility, the right allocation approach of free distribution followed by exchange may offer the most desirable package of features. This approach can yield dischargers savings over the expenses of present uniform regulations as well as provide incentives for efficient allocation of treatment efforts. 25 references, 1 figure, 5 tables.

  7. 78 FR 11179 - Auction of Lower and Upper Paging Bands Licenses Scheduled for July 16, 2013; Comment Sought on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-15

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION Auction of Lower and Upper Paging Bands Licenses Scheduled for July 16, 2013; Comment Sought on Competitive Bidding Procedures for Auction 95 AGENCY: Federal Communications Commission. ACTION:...

  8. 76 FR 1158 - Auction of 700 MHz Band Licenses Scheduled for July 19, 2011; Comment Sought on Competitive...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-07

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION Auction of 700 MHz Band Licenses Scheduled for July 19, 2011; Comment Sought on Competitive Bidding Procedures for Auction 92 AGENCY: Federal Communications Commission. ACTION: Notice. ]...

  9. A possible formation mechanism of double-walled and multi-walled carbon nanotube: a molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Han, Dianrong; Luo, Chenglin; Dai, Yafei; Zhu, Xingfeng

    2016-09-01

    Molecular dynamics simulations based on an empirical potential were performed to study the interaction of graphene nanoribbons and the single-walled carbon nanotubes. The results indicated that a piece of graphene nanoribbon can form a tube structure inside or outside single-walled carbon nanotubes spontaneously under certain condition. Based on this kind of spontaneous phenomenon, we proposed a new possible formation mechanism of double walled carbon nanotube and multi-walled carbon nanotube, and suggested the possibility of controlling the structure of double-walled carbon nanotube and/or multi-walled carbon nanotube.

  10. 78 FR 72081 - Closed Auction of AM Broadcast Construction Permits Scheduled for May 6, 2014; Comment Sought on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-02

    ... be a ``closed'' auction; only those entities listed in Attachment A to the Auction 84 Comment Public..., 2013. The complete text of the Auction 84 Comment Public Notice, including all attachments and related... Notice and its attachments, as well as related Commission documents, also may be purchased from...

  11. 30 CFR 285.308 - How will MMS conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and RUE grants? 285.308 Section 285.308 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF... Obtaining Row Grants and Rue Grants § 285.308 How will MMS conduct an auction for ROW grants and RUE grants... comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The auction...

  12. 77 FR 60690 - Auction of FM Broadcast Construction Permits Scheduled for March 26, 2013; Comment Sought on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ... COMMISSION Auction of FM Broadcast Construction Permits Scheduled for March 26, 2013; Comment Sought on.... SUMMARY: This document announces the auction of certain FM broadcast construction permits scheduled to... auction of certain FM broadcast construction permits and seek comment on the procedures to be used...

  13. 7 CFR 1955.131 - Auctioneers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property Use of Contractors to Dispose of..., location, advertising, broker cooperation, innovations, mechanics of sale, sample advertising,...

  14. 30 CFR 585.220 - What auction format may BOEM use in a lease sale?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Issuance of OCS Renewable Energy Leases Competitive Lease Award Process § 585.220 What auction format may... award renewable energy leases and will use one of the following auction formats, as determined...

  15. 30 CFR 285.220 - What auction format may MMS use in a lease sale?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OFFSHORE RENEWABLE ENERGY ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Issuance of OCS Renewable Energy Leases Competitive Lease Award Process § 285.220 What auction format may MMS use... renewable energy leases and will use one of the following auction formats, as determined through the...

  16. 30 CFR 585.220 - What auction format may BOEM use in a lease sale?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Issuance of OCS Renewable Energy Leases Competitive Lease Award Process § 585.220 What auction format may... award renewable energy leases and will use one of the following auction formats, as determined...

  17. 30 CFR 285.220 - What auction format may MMS use in a lease sale?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE RENEWABLE ENERGY ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Issuance of OCS Renewable Energy Leases Competitive Lease Award Process § 285... competitive auctions to award renewable energy leases and will use one of the following auction formats,...

  18. 30 CFR 585.220 - What auction format may BOEM use in a lease sale?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... INTERIOR OFFSHORE RENEWABLE ENERGY AND ALTERNATE USES OF EXISTING FACILITIES ON THE OUTER CONTINENTAL SHELF Issuance of OCS Renewable Energy Leases Competitive Lease Award Process § 585.220 What auction format may... award renewable energy leases and will use one of the following auction formats, as determined...

  19. 31 CFR 356.22 - Does the Treasury have any limitations on auction awards?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Does the Treasury have any limitations on auction awards? 356.22 Section 356.22 Money and Finance: Treasury Regulations Relating to Money..., PUBLIC DEBT SERIES NO. 1-93) Determination of Auction Awards; Settlement § 356.22 Does the Treasury...

  20. 29 CFR 780.620 - Minimum wage for livestock auction work.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Minimum wage for livestock auction work. 780.620 Section 780.620 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR... for Exemption § 780.620 Minimum wage for livestock auction work. The application of the exemption...

  1. 29 CFR 780.620 - Minimum wage for livestock auction work.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Minimum wage for livestock auction work. 780.620 Section 780.620 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR... for Exemption § 780.620 Minimum wage for livestock auction work. The application of the exemption...

  2. 29 CFR 780.620 - Minimum wage for livestock auction work.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Minimum wage for livestock auction work. 780.620 Section 780.620 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR... for Exemption § 780.620 Minimum wage for livestock auction work. The application of the exemption...

  3. 29 CFR 780.620 - Minimum wage for livestock auction work.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Minimum wage for livestock auction work. 780.620 Section 780.620 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR... for Exemption § 780.620 Minimum wage for livestock auction work. The application of the exemption...

  4. 29 CFR 780.620 - Minimum wage for livestock auction work.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Minimum wage for livestock auction work. 780.620 Section 780.620 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR... for Exemption § 780.620 Minimum wage for livestock auction work. The application of the exemption...

  5. Sold! The Elementary Classroom Auction as Learning Tool of Communication and Economics

    ERIC Educational Resources Information Center

    Boyd, Josh; Boyd, Gina

    2014-01-01

    An auction, though an economic tool, is essentially a performance dependent on communication (Smith, 1989). The auctioneer dictates the pace, asks for bids, and acknowledges responses; the enterprise is controlled by a voice (Boyce, 2001). Bidders must listen and respond strategically to the communication of the people around them. An auction…

  6. Are Structural Estimates of Auction Models Reasonable? Evidence from Experimental Data

    ERIC Educational Resources Information Center

    Bajari, Patrick; Hortacsu, Ali

    2005-01-01

    Recently, economists have developed methods for structural estimation of auction models. Many researchers object to these methods because they find the strict rationality assumptions to be implausible. Using bid data from first-price auction experiments, we estimate four alternative structural models: (1) risk-neutral Bayes-Nash, (2) risk-averse…

  7. 9 CFR 2.76 - Records: Operators of auction sales and brokers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Records: Operators of auction sales and brokers. 2.76 Section 2.76 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE REGULATIONS Records § 2.76 Records: Operators of auction sales...

  8. 9 CFR 2.76 - Records: Operators of auction sales and brokers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Records: Operators of auction sales and brokers. 2.76 Section 2.76 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE REGULATIONS Records § 2.76 Records: Operators of auction sales...

  9. 9 CFR 2.76 - Records: Operators of auction sales and brokers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Records: Operators of auction sales and brokers. 2.76 Section 2.76 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE REGULATIONS Records § 2.76 Records: Operators of auction sales...

  10. 9 CFR 2.76 - Records: Operators of auction sales and brokers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Records: Operators of auction sales and brokers. 2.76 Section 2.76 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE REGULATIONS Records § 2.76 Records: Operators of auction sales...

  11. 9 CFR 2.76 - Records: Operators of auction sales and brokers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Records: Operators of auction sales and brokers. 2.76 Section 2.76 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE REGULATIONS Records § 2.76 Records: Operators of auction sales...

  12. Pricing strategies, the strength of bidding intentions, and online auction performance: a cross-cultural study.

    PubMed

    Peng, Yu-Shu; Jan, Lih-Tsyr

    2009-10-01

    Over the past decade, electronic markets based on the Internet, particularly online auctions, have become popular venues for conducting business. Previous studies often focused on the construction of the best bidding model, while few studies have tried to integrate multiple pricing strategies to predict the probability of closing an auction and the price premium. This study constructs a mediated model to examine the relationship among pricing strategies, the strength of bidding intentions, and online auction performance. The sample consists of 1,055 auctions of iPod MP3 players from eBay Web sites in Hong Kong, Singapore, Belgium, and France. Empirical results show that the pricing strategies directly influence both the probability of closing an auction and the level of price premium. The pricing strategies also indirectly influence the price premium through the mediating effect of the strength of bidding intentions. PMID:19817564

  13. Pricing strategies, the strength of bidding intentions, and online auction performance: a cross-cultural study.

    PubMed

    Peng, Yu-Shu; Jan, Lih-Tsyr

    2009-10-01

    Over the past decade, electronic markets based on the Internet, particularly online auctions, have become popular venues for conducting business. Previous studies often focused on the construction of the best bidding model, while few studies have tried to integrate multiple pricing strategies to predict the probability of closing an auction and the price premium. This study constructs a mediated model to examine the relationship among pricing strategies, the strength of bidding intentions, and online auction performance. The sample consists of 1,055 auctions of iPod MP3 players from eBay Web sites in Hong Kong, Singapore, Belgium, and France. Empirical results show that the pricing strategies directly influence both the probability of closing an auction and the level of price premium. The pricing strategies also indirectly influence the price premium through the mediating effect of the strength of bidding intentions.

  14. The design and analysis of a double swivel toggle release mechanism for the Orbiter stabilized payload deployment system

    NASA Technical Reports Server (NTRS)

    King, Guy L.; Tsai, Ted

    1989-01-01

    The NASA Stabilized Payload Deployment System (SPDS) is discussed. The lightweight and heavy-duty system rolls payloads over the orbiter's side rather than ejecting them upward. The system will enhance the orbiter capability of carrying larger and heavier payloads. The design, function, and analysis of a new three-pin double swivel toggle release mechanism which is crucial to the successful deployment of the SPDS are described.

  15. A mechanism for weak double layers and coherent low-frequency electrostatic wave activity in the solar wind

    NASA Astrophysics Data System (ADS)

    Singh Lakhina, Gurbax; Singh, Satyavir

    2016-07-01

    A mechanism for the weak double layers and coherent low-frequency electrostatic wave activity observed by Wind spacecraft in the solar wind at 1 AU is proposed in terms of ion-acoustic solitons and double layers. The solar wind plasma is modelled by a three component plasma consisting of fluid hot protons, hot alpha particles streaming with respect to protons, and suprathermal electrons having κ- distribution. This system supports two types of, slow and fast, ion-acoustic solitary waves. The fast ion-acoustic mode is similar to the ion-acoustic mode of proton-electron plasma, and can support only positive potential solitons. The slow ion-acoustic mode is a new mode that occurs due to the presence of alpha particles. This mode can support both positive and negative solitons and double layers. An increase of the κ- index leads to an increase in the critical Mach number, maximum Mach number and the maximum amplitude of both slow and fast ion-acoustic solitons. The slow ion-acoustic double layer can explain the amplitudes and widths, but not shapes, of the weak double layers (WDLs) observed in the solar wind at 1 AU by Wind spacecraft. The Fourier transform of the slow ion-acoustic solitons/double layers would produce broadband low-frequency electrostatic waves having main peaks between 0.35 kHz to 1.6 kHz, with electric field in the range of E = (0.01 - 0.7 ) mV/m, in excellent agreement with the observed low-frequency electrostatic wave activity in the solar wind at 1 AU.

  16. Double-inversion mechanisms of the X⁻ + CH₃Y [X,Y = F, Cl, Br, I] SN2 reactions.

    PubMed

    Szabó, István; Czakó, Gábor

    2015-03-26

    The double-inversion and front-side attack transition states as well as the proton-abstraction channels of the X(-) + CH3Y [X,Y = F, Cl, Br, I] reactions are characterized by the explicitly correlated CCSD(T)-F12b/aug-cc-pVTZ(-PP) level of theory using small-core relativistic effective core potentials and the corresponding aug-cc-pVTZ-PP bases for Br and I. In the X = F case the double-inversion classical(adiabatic) barrier heights are 28.7(25.6), 15.8(13.4), 13.2(11.0), and 8.6(6.6) kcal mol(-1) for Y = F, Cl, Br, and I, respectively, whereas the barrier heights are in the 40-90 kcal mol(-1) range for the other 12 reactions. The abstraction channels are always above the double-inversion saddle points. For X = F, the front-side attack classical(adiabatic) barrier heights, 45.8(44.8), 31.0(30.3), 24.7(24.2), and 19.5(19.3) kcal mol(-1) for Y = F, Cl, Br, and I, respectively, are higher than the corresponding double-inversion ones, whereas for the other systems the front-side attack saddle points are in the 35-70 kcal mol(-1) range. The double-inversion transition states have XH···CH2Y(-) structures with Cs point-group symmetry, and the front-side attack saddle points have either Cs (X = F or X = Y) or C1 symmetry with XCY angles in the 78-88° range. On the basis of the previous reaction dynamics simulations and the minimum energy path computations along the inversion coordinate of selected XH···CH2Y(-) systems, we suggest that the double inversion may be a general mechanism for SN2 reactions.

  17. Fault structure and mechanics of the Hayward Fault, California from double-difference earthquake locations

    USGS Publications Warehouse

    Waldhauser, F.; Ellsworth, W.L.

    2002-01-01

    The relationship between small-magnitude seismicity and large-scale crustal faulting along the Hayward Fault, California, is investigated using a double-difference (DD) earthquake location algorithm. We used the DD method to determine high-resolution hypocenter locations of the seismicity that occurred between 1967 and 1998. The DD technique incorporates catalog travel time data and relative P and S wave arrival time measurements from waveform cross correlation to solve for the hypocentral separation between events. The relocated seismicity reveals a narrow, near-vertical fault zone at most locations. This zone follows the Hayward Fault along its northern half and then diverges from it to the east near San Leandro, forming the Mission trend. The relocated seismicity is consistent with the idea that slip from the Calaveras Fault is transferred over the Mission trend onto the northern Hayward Fault. The Mission trend is not clearly associated with any mapped active fault as it continues to the south and joins the Calaveras Fault at Calaveras Reservoir. In some locations, discrete structures adjacent to the main trace are seen, features that were previously hidden in the uncertainty of the network locations. The fine structure of the seismicity suggest that the fault surface on the northern Hayward Fault is curved or that the events occur on several substructures. Near San Leandro, where the more westerly striking trend of the Mission seismicity intersects with the surface trace of the (aseismic) southern Hayward Fault, the seismicity remains diffuse after relocation, with strong variation in focal mechanisms between adjacent events indicating a highly fractured zone of deformation. The seismicity is highly organized in space, especially on the northern Hayward Fault, where it forms horizontal, slip-parallel streaks of hypocenters of only a few tens of meters width, bounded by areas almost absent of seismic activity. During the interval from 1984 to 1998, when digital

  18. Physical Mechanisms and Scaling Laws of K-Shell Double Photoionization

    SciTech Connect

    Hoszowska, J.; Dousse, J.-Cl.; Berset, M.; Cao, W.; Fennane, K.; Kayser, Y.; Szlachetko, J.; Szlachetko, M.; Kheifets, A. K.; Bray, I.; Kavcic, M.

    2009-02-20

    We report on the photon energy dependence of the K-shell double photoionization (DPI) of Mg, Al, and Si. The DPI cross sections were derived from high-resolution measurements of x-ray spectra following the radiative decay of the K-shell double vacancy states. Our data evince the relative importance of the final-state electron-electron interaction to the DPI. By comparing the double-to-single K-shell photoionization cross-section ratios for neutral atoms with convergent close-coupling calculations for He-like ions, the effect of outer shell electrons on the K-shell DPI process is assessed. Universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms is revealed.

  19. [Research on the mechanical properties of bone scaffold reinforced by magnesium alloy/bioceramics composite with stereolithography double channels].

    PubMed

    Li, Changhai; Lian, Qin; Zhuang, Pei; Wang, Junzhong; Li, Dichen

    2015-02-01

    Focusing on the poor mechanical strength of porous bioceramics bone scaffold, and taking into account of the good mechanical properties of biodegradable magnesium alloy, we proposed a novel method to fabricate magnesium alloy/bioceramics composite bone scaffold with stereolithography double channels. Firstly, a scaffold structure without mutually connected double channels was designed. Then, an optimized bioceramics scaffold was fabricated according to stereolithography and gel-casing. Molten AZ31 magnesium alloy was perfused into the secondary channel of scaffold by low-pressure casting, and magnesium alloy/bioceramics composite bone scaffold was obtained when magnesium alloy was solidified. The compression test showed that the strength of bioceramics scaffold with only one channel and without magnesium alloy was (9.76 ± 0.64) MPa, while the strength of magnesium alloy/bioceramics composite scaffold with double channels was (17.25 ± 0.88) MPa. It can be concluded that the magnesium alloy/bioceramics composite is obviously able to improve the scaffold strength.

  20. RecBCD is required to Complete Chromosomal Replication: Implications for Double-Strand Break Frequencies and Repair Mechanisms

    PubMed Central

    Courcelle, Justin; Wendel, Brian M.; Livingstone, Dena D.; Courcelle, Charmain T.

    2015-01-01

    Several aspects of the mechanism of homologous double strand break repair remain unclear. Although intensive efforts have focused on how recombination reactions initiate, far less is known about the molecular events that follow. Based upon biochemical studies, current models propose that RecBCD processes double strand ends and loads RecA to initiate recombinational repair. However, recent studies have shown that RecBCD plays a critical role in completing replication events on the chromosome through a mechanism that does not involve RecA or recombination. Here, we examine several studies, both early and recent, that suggest RecBCD also operates late in the recombination process- after initiation, strand invasion, and crossover resolution have occurred. Similar to its role in completing replication, we propose a model in which RecBCD is required to resect and resolve the DNA synthesis associated with homologous recombination at the point where the missing sequences on the broken molecule have been restored. We explain how the impaired ability to complete chromosome replication in recBC and recD mutants is likely to account for the loss of viability and genome instability in these mutants, and conclude that spontaneous double strand breaks and replication fork collapse occur far less frequently than previously speculated. PMID:26003632

  1. Ambient-temperature Conditioning as a Probe of Double-C Transformation Mechanisms in Pu-2.0 at. % Ga

    SciTech Connect

    Jeffries, J R; Blobaum, K M; Wall, M A; Schwartz, A J

    2008-04-02

    The gallium-stabilized Pu-2.0 at. % Ga alloy undergoes a partial or incomplete low-temperature martensitic transformation from the metastable {delta} phase to the gallium-containing, monoclinic {alpha}{prime} phase near -100 C. This transformation has been shown to occur isothermally and it displays anomalous double-C kinetics in a time-temperature-transformation (TTT) diagram, where two nose temperatures anchoring an upper- and lower-C describe minima in the time for the initiation of transformation. The underlying mechanisms responsible for the double-C behavior are currently unresolved, although recent experiments suggest that a conditioning treatment--wherein, following an anneal at 375 C, the sample is held at a sub-anneal temperature for a period of time--significantly influences the upper-C of the TTT diagram. As such, elucidating the effects of the conditioning treatment upon the {delta} {yields} {alpha}{prime} transformation can provide valuable insights into the fundamental mechanisms governing the double-C kinetics of the transition. Following a high-temperature anneal, a differential scanning calorimeter (DSC) was used to establish an optimal conditioning curve that depicts the amount of {alpha}{prime} formed during the transformation as a function of conditioning temperature for a specified time. With the optimal conditioning curve as a baseline, the DSC was used to explore the circumstances under which the effects of the conditioning treatment were destroyed, resulting in little or no transformation.

  2. Identification of shareholder ethics and responsibilities in online reverse auctions for construction projects.

    PubMed

    Hatipkarasulu, Yilmaz; Gill, James H

    2004-04-01

    The increasing number of companies providing internet services and auction tools helped popularize the online reverse auction trend for purchasing commodities and services in the last decade. As a result, a number of owners, both public and private, accepted the online reverse auctions as the bidding technique for their construction projects. Owners, while trying to minimize their costs for construction projects, are also required to address their ethical responsibilities to the shareholders. In the case of online reverse auctions for construction projects, the ethical issues involved in the bidding technique directly reflects on the owner's ethical and social responsibilities to their shareholders. The goal of this paper is to identify the shareholder ethics and responsibilities in online reverse auctions for construction projects by analyzing the ethical issues for the parties involved in the process. The identification of the ethical issues and responsibilities requires clear definition and understanding of professional ethics and the roles of the involved parties. In this paper, first, the concept of professional ethics and social responsibility is described in a general form. To illustrate the ethical issues and responsibilities, a sample case of bidding for a construction project using online reverse auction techniques is presented in which the shareholders were actively involved in questioning the ethical issues. The issues involved in the bidding process and their reflection on the shareholder responsibilities are described and analyzed for each stage of the process. A brief discussion of the overall process is also included to address the general ethical issues involved in online reverse auctions.

  3. Fabrication of double-aperture hololens imaging system: application to mechanics

    NASA Astrophysics Data System (ADS)

    Yadav, H. L.; Kumari, Neelam; Bhushan, Ravi; Mallick, Anshuman; Gupta, B. N.

    2004-06-01

    Duffy suggested the use of double-aperture imaging system for the measurement of in-plane displacement component. In this arrangement, twin apertures are placed symmetrically over the imaging lens. This imaging system is used in speckle metrology to measure component of displacement parallel to the line joining the two apertures. The imaging lens used in such configuration need not be diffraction limited over the entire lens aperture, but only over the two small areas encompassed by the two apertures. In present work, compact holographic lenses have been used to generate the two apertures of Duffy's double-aperture interferometer. This imaging system has been used in speckle metrology to measure crack mouth opening displacement (CMOD) in an aluminium beam specimen having central edge crack subjected to three point bending. Experimental results are in good agreement with theoretical predictions. Present experimental investigation reveals that compact holographic lenses can be used advantageously to generate apertures of double-aperture speckle interferometer for its use in the measurement of in-plane displacement component.

  4. Double-strand-break repair recombination in Escherichia coli: physical evidence for a DNA replication mechanism in vivo

    PubMed Central

    Motamedi, Mohammad R.; Szigety, Susan K.; Rosenberg, Susan M.

    1999-01-01

    DNA double-strand-break repair (DSBR) is, in many organisms, accomplished by homologous recombination. In Escherichia coli DSBR was thought to result from breakage and reunion of parental DNA molecules, assisted by known endonucleases, the Holliday junction resolvases. Under special circumstances, for example, SOS induction, recombination forks were proposed to initiate replication. We provide physical evidence that this is a major alternative mechanism in which replication copies information from one chromosome to another generating recombinant chromosomes in normal cells in vivo. This alternative mechanism can occur independently of known Holliday junction cleaving proteins, requires DNA polymerase III, and produces recombined DNA molecules that carry newly replicated DNA. The replicational mechanism underlies about half the recombination of linear DNA in E. coli; the other half occurs by breakage and reunion, which we show requires resolvases, and is replication-independent. The data also indicate that accumulation of recombination intermediates promotes replication dramatically. PMID:10557215

  5. Determination of Constitutive Equation for Thermo-mechanical Processing of INCONEL 718 Through Double Multivariate Nonlinear Regression Analysis

    NASA Astrophysics Data System (ADS)

    Hussain, Mirza Zahid; Li, Fuguo; Wang, Jing; Yuan, Zhanwei; Li, Pan; Wu, Tao

    2015-07-01

    The present study comprises the determination of constitutive relationship for thermo-mechanical processing of INCONEL 718 through double multivariate nonlinear regression, a newly developed approach which not only considers the effect of strain, strain rate, and temperature on flow stress but also explains the interaction effect of these thermo-mechanical parameters on flow behavior of the alloy. Hot isothermal compression experiments were performed on Gleeble-3500 thermo-mechanical testing machine in the temperature range of 1153 to 1333 K within the strain rate range of 0.001 to 10 s-1. The deformation behavior of INCONEL 718 is analyzed and summarized by establishing the high temperature deformation constitutive equation. The calculated correlation coefficient ( R) and average absolute relative error ( AARE) underline the precision of proposed constitutive model.

  6. The unexpected mechanism of carbonyl hydrosilylation catalyzed by (Cp)(ArN[double bond, length as m-dash])Mo(H)(PMe(3)).

    PubMed

    Shirobokov, Oleg G; Gorelsky, Serge I; Simionescu, Razvan; Kuzmina, Lyudmila G; Nikonov, Georgii I

    2010-11-01

    Complex (Cp)(ArN[double bond, length as m-dash])Mo(H)(PMe(3)) (2, Ar = 2,6-diisopropylphenyl) catalyzes the hydrosilylation of carbonyls by an unexpected associative mechanism. Complex 2 also reacts with PhSiH(3) by a σ-bond metathesis mechanism to give the silyl derivative (Cp)(ArN[double bond, length as m-dash])Mo(SiH(2)Ph)(PMe(3)).

  7. A fully coupled constitutive model for thermo-hydro-mechanical analysis in elastic media with double porosity

    NASA Astrophysics Data System (ADS)

    Khalili, N.; Selvadurai, A. P. S.

    2003-12-01

    The partial differential equations governing non-isothermal flow and deformation in an elastic medium with double porosity are presented. The governing equations satisfy an effective stress concept, Darcy's law, Fourier' law and the equations of Hookean thermoelasticity. The equations are derived using a systematic macroscopic approach that satisfies conservation laws applicable to balance of linear momentum, mass and energy. The Thermo-Hydro-Mechanical coupling take into account processes associated with: thermal expansion, thermal convection by moving fluid, fluid flux due to temperature gradients, heat flux due to pressure gradients, fluid and heat exchange between the two pore system, and the heat of phase compression.

  8. Importance of the recoil contribution in Two Step 2 mechanism for the electron impact double ionization process

    NASA Astrophysics Data System (ADS)

    Li, C.; Staicu Casagrande, E. M.; Lahmam-Bennani, A.

    2014-04-01

    The second order, Two-Step-2 (TS2) mechanism for electron impact double ionization (DI) of various targets at intermediate incident energy is investigated based on a kinematical analysis which assumes the DI to result from two successive (e,2e) single ionization (SI) events. The results show that under the present kinematics, the inclusion of the recoil scattering in each of these (e,2e)-SI steps (in previous studies only the binary scattering was considered) allows a more detailed understanding of the various peaks observed in the experimental angular distributions of the ejected electrons in both (e,3-1e) and (e,3e) experiments.

  9. Probable new type of reaction mechanism: Double. cap alpha. direct transfer process

    SciTech Connect

    Xu Shu-wei; Wu Guo-hua; Miao Rong-zhi; Han Fei

    1983-10-01

    It is assumed that /sup 8/Be consists of two ..cap alpha.. particles which are close to each other in configuration space. A spectroscopic density of /sup 8/Be cluster in the residue nuclei is then obtained, which is proportional to the square of the preformation probability of ..cap alpha.. particle at nuclear surface. Using the improved method of parametrization of EFR-DWBA overlap integral,/sup 1//sup en-dash//sup 2/ we calculate the double differential energy spectra and angular distributions of ..cap alpha.. particles for the reactions /sup 209/Bi (/sup 12/C, ..cap alpha..) /sup 217/Fr and extract the preformation probability of ..cap alpha.. particle at the surface of /sup 217/Fr nuclei from fitting the experimental data. The agreement within the range of calculation error between the preformation probabilities extracted from transfer reactions and ..cap alpha.. decay suggests that the reaction /sup 209/Bi(/sup 12/C, ..cap alpha..) /sup 217/Fr may be explained as a double ..cap alpha.. direct transfer process.

  10. Mechanism of drug release from double-walled PDLLA(PLGA) microspheres

    PubMed Central

    Xu, Qingxing; Chin, Shi En; Wang, Chi-Hwa; Pack, Daniel W.

    2013-01-01

    The drug release and degradation behavior of two double-walled microsphere formulations consisting of a doxorubicin loaded poly(D,L-lactic-co-glycolic acid) (PLGA) core (~46 kDa) surrounded by a poly(D,L-lactic acid) (PDLLA) shell layer (~55 and 116 kDa) were examined. It was postulated that different molecular weights of the shell layer could modulate the erosion of the outer coating and limit the occurrence of water penetration into the inner drug-loaded core on various time scales, and therefore control the drug release from the microspheres. For both microsphere formulations, the drug release profiles were observed to be similar. The degradation of the microspheres was monitored for a period of about nine weeks and analyzed using scanning electron microscopy, laser scanning confocal microscopy, and gel permeation chromatography. Interestingly, both microsphere formulations exhibited occurrence of bulk erosion of PDLLA on a similar time scale despite different PDLLA molecular weights forming the shell layer. The shell layer of the double-walled microspheres served as an effective diffusion barrier during the initial lag phase period and controlled the release rate of the hydrophilic drug independent of the molecular weight of the shell layer. PMID:23453059

  11. Bid distribution derived from consistent mixed strategy in lowest unique bid auction

    NASA Astrophysics Data System (ADS)

    Zhao, Yinan; Chen, Qinghua; Wang, Yougui

    2014-12-01

    The Lowest Unique Bid Auction (LUBA) booms recently through the Internet. A typical distribution pattern of bid price in this reverse auction has been found and needs to be interpreted. The distribution curve is a decreasing one whose slope has a close relationship with the number of agents participating in the auction. To explain this stylized fact, we develop a model assuming that agents prefer to bid on the price at which the probability of winning is higher. The bid distributions of actual auctions with the number of agents less than 200 can be fitted very well using the parameters for the value of items and the number of bids. When this number becomes larger, however, a deviation occurs between prediction and empirical data, which can be adjusted by introducing cognitive illusion of the bid number.

  12. 31 CFR 356.33 - Does the Treasury have any discretion in the auction process?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AND ISSUE OF MARKETABLE BOOK-ENTRY TREASURY BILLS, NOTES, AND BONDS (DEPARTMENT OF THE TREASURY... provide a public notice if we change any auction provision, term, or condition. (c) We reserve the...

  13. 31 CFR 356.33 - Does the Treasury have any discretion in the auction process?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SALE AND ISSUE OF MARKETABLE BOOK-ENTRY TREASURY BILLS, NOTES, AND BONDS (DEPARTMENT OF THE TREASURY... provide a public notice if we change any auction provision, term, or condition. (c) We reserve the...

  14. 49 CFR 580.9 - Odometer record retention for auction companies.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... retain at its primary place of business in an order that is appropriate to business requirements and that... following records: (a) The name of the most recent owner (other than the auction company); (b) The name...

  15. Accommodating individual preferences in nurse scheduling via auctions and optimization.

    PubMed

    De Grano, Melanie L; Medeiros, D J; Eitel, David

    2009-09-01

    This paper describes a two-stage approach to nurse scheduling that considers both nurse preferences and hospital constraints. In the auction stage, nurses bid for their preferred working shifts and rest days using "points". An optimization model awards shifts to the highest bidders insofar as possible while maintaining hospital requirements. In the schedule completion stage, an optimization model allocates the unfilled shifts to nurses who have not yet met their minimum required hours. The approach is demonstrated via a case study in the emergency department at York Hospital. A schedule with a high percentage of awarded bids was generated in a few minutes of computer time. Further experimentation suggests that the approach works well under a variety of conditions.

  16. Accommodating individual preferences in nurse scheduling via auctions and optimization.

    PubMed

    De Grano, Melanie L; Medeiros, D J; Eitel, David

    2009-09-01

    This paper describes a two-stage approach to nurse scheduling that considers both nurse preferences and hospital constraints. In the auction stage, nurses bid for their preferred working shifts and rest days using "points". An optimization model awards shifts to the highest bidders insofar as possible while maintaining hospital requirements. In the schedule completion stage, an optimization model allocates the unfilled shifts to nurses who have not yet met their minimum required hours. The approach is demonstrated via a case study in the emergency department at York Hospital. A schedule with a high percentage of awarded bids was generated in a few minutes of computer time. Further experimentation suggests that the approach works well under a variety of conditions. PMID:19739357

  17. Methotrexate intercalated layered double hydroxides with the mediation of surfactants: Mechanism exploration and bioassay study.

    PubMed

    Dai, Chao-Fan; Tian, De-Ying; Li, Shu-Ping; Li, Xiao-Dong

    2015-12-01

    Methotrexatum intercalated layered double hydroxides (MTX/LDHs) hybrids were synthesized by the co-precipitation method and three kinds of nonionic surfactants with different hydrocarbon chain lengths were used. The resulting hybrids were then characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). XRD and FTIR investigations manifest the successful intercalation of MTX anions into the interlayer of LDHs. TEM graphs indicate that the morphology of the hybrids changes with the variation of the chain length of the surfactants, i.e., the particles synthesized using polyethylene glycol (PEG-7) present regular disc morphology with good monodispersity, while samples with the mediation of alkyl polyglycoside (APG-14) are heavily aggregated and samples with the addition of polyvinylpyrrolidone (PVP-10) exhibit irregular branches. Furthermore, the release and bioassay experiments show that monodisperse MTX/LDHs present good controlled-release and are more efficient in the suppression of the tumor cells. PMID:26354264

  18. Methotrexate intercalated layered double hydroxides with the mediation of surfactants: Mechanism exploration and bioassay study.

    PubMed

    Dai, Chao-Fan; Tian, De-Ying; Li, Shu-Ping; Li, Xiao-Dong

    2015-12-01

    Methotrexatum intercalated layered double hydroxides (MTX/LDHs) hybrids were synthesized by the co-precipitation method and three kinds of nonionic surfactants with different hydrocarbon chain lengths were used. The resulting hybrids were then characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). XRD and FTIR investigations manifest the successful intercalation of MTX anions into the interlayer of LDHs. TEM graphs indicate that the morphology of the hybrids changes with the variation of the chain length of the surfactants, i.e., the particles synthesized using polyethylene glycol (PEG-7) present regular disc morphology with good monodispersity, while samples with the mediation of alkyl polyglycoside (APG-14) are heavily aggregated and samples with the addition of polyvinylpyrrolidone (PVP-10) exhibit irregular branches. Furthermore, the release and bioassay experiments show that monodisperse MTX/LDHs present good controlled-release and are more efficient in the suppression of the tumor cells.

  19. Physical mechanism of beam splitting based on reflective embedded double-layer grating

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Li, Hongtao; Shu, Wenhao; Li, Wenhua; Chen, Li; Lei, Liang; Zhou, Jinyun

    2016-12-01

    It is not easy to achieve high performance for conventional beam splitters, such as high efficiency, good uniformity, polarization-independence, and wide bandwidth. A reflective embedded double-layer grating is described for beam splitting. With optimized grating profiles, the novel beam splitter can diffract both TE and TM polarizations into two orders with high performance. For the easy production, the fabrication tolerance is investigated and given. Most importantly, efficiencies more than 45% can be split into two orders within the wide bandwidth of 1412-1647 nm for TE polarization. The beam splitter based on multilayer coatings is sensitive to the incident angle and wavelength. And the bandwidth needs to be improved for the beam splitter based on simple grating. The design is of benefit for the performance improvement of the beam splitter by new grating configuration compared with the conventional simple grating.

  20. Combining auctions and performance-based payments in a forest enrichment field trial in Western Kenya.

    PubMed

    Khalumba, Mercelyne; Wünscher, Tobias; Wunder, Sven; Büdenbender, Mirjam; Holm-Müller, Karin

    2014-06-01

    Cost-effectiveness is an important aspect in the assessment of payments for environmental services (PES) initiatives. In participatory field trials with communities in Western Kenya, we combined procurement auctions for forest enrichment contracts with performance-based payments and compared the outcomes with a baseline scenario currently used by the Kenyan Forest Service. Procurement auctions were the most cost-effective. The competitive nature of the auction reduced contracting expenses (provision costs), and the result-oriented payments provided additional incentives to care for the planted seedlings, resulting in their improved survival rates (service quantity). These gains clearly exceeded increases in transaction costs associated with conducting an auction. The number of income-poor auction participants and winners was disproportionately high and local institutional buy-in was remarkably strong. Our participatory approach may, however, require adaptations when conducted at a larger scale. Although the number of contracts we monitored was limited and prohibited the use of statistical tests, our study is one of the first to reveal the benefits of using auctions for PES in developing countries.

  1. Combining auctions and performance-based payments in a forest enrichment field trial in Western Kenya.

    PubMed

    Khalumba, Mercelyne; Wünscher, Tobias; Wunder, Sven; Büdenbender, Mirjam; Holm-Müller, Karin

    2014-06-01

    Cost-effectiveness is an important aspect in the assessment of payments for environmental services (PES) initiatives. In participatory field trials with communities in Western Kenya, we combined procurement auctions for forest enrichment contracts with performance-based payments and compared the outcomes with a baseline scenario currently used by the Kenyan Forest Service. Procurement auctions were the most cost-effective. The competitive nature of the auction reduced contracting expenses (provision costs), and the result-oriented payments provided additional incentives to care for the planted seedlings, resulting in their improved survival rates (service quantity). These gains clearly exceeded increases in transaction costs associated with conducting an auction. The number of income-poor auction participants and winners was disproportionately high and local institutional buy-in was remarkably strong. Our participatory approach may, however, require adaptations when conducted at a larger scale. Although the number of contracts we monitored was limited and prohibited the use of statistical tests, our study is one of the first to reveal the benefits of using auctions for PES in developing countries. PMID:24665907

  2. A deployment mechanism for the double roll-out flexible solar array on the space telescope

    NASA Technical Reports Server (NTRS)

    Cawsey, T. R.

    1982-01-01

    A roll-out flexible array which provides more than 4 kW of power for the space telescope was developed. The Array is configured as two wings. The deployment mechanism for each wing is based on flight-proven FRUSA design. Modifications have been incorporated to accommodate an increase in size and mission requirements. The assembly and operation of the deployment mechanism are described together with environmental and functional tests results.

  3. Green Auctions and Reduction of Information Rents in Payments for Environmental Services: An Experimental Investigation in Sunan County, Northwestern China

    PubMed Central

    Deng, Xiaohong; Xu, Zhongmin

    2015-01-01

    Reducing information rents is an important task for government agencies wishing to purchase maximal environmental services with limited budgets. This paper reports on several green auction options for reducing information rents and improving the performance of the “Grain for Green” Payments for environmental services (PES) program implemented in northwestern China. In r experimental auctions and investigations, door-to-door interviews were conducted and bidding envelopes and survey questionnaires were used to determine the offers and the foregone profits of the participants. Three scenarios are analyzed in this paper: a uniform price auction, a discriminatory price auction, and an opportunity-cost system. The results show that compared to the uniform price auction system, the other auction systems can increase the cost-effectiveness of conservation contracting. Competitive bidding can reveal true opportunity costs and can reduce information rents extracted from the government by farmers using private information. The demographics and average bids of these auction types were also analyzed. “Perfect information” in the opportunity-cost offer system has the best performance but is very hard to implement in reality. The results of this research show that the auction is a valuable tool for purchasing conservation contracts in northwestern China, but that in the future, the performance of these auctions should be studied with relaxed model assumptions. PMID:25793263

  4. Green auctions and reduction of information rents in payments for environmental services: an experimental investigation in Sunan County, northwestern China.

    PubMed

    Deng, Xiaohong; Xu, Zhongmin

    2015-01-01

    Reducing information rents is an important task for government agencies wishing to purchase maximal environmental services with limited budgets. This paper reports on several green auction options for reducing information rents and improving the performance of the "Grain for Green" Payments for environmental services (PES) program implemented in northwestern China. In r experimental auctions and investigations, door-to-door interviews were conducted and bidding envelopes and survey questionnaires were used to determine the offers and the foregone profits of the participants. Three scenarios are analyzed in this paper: a uniform price auction, a discriminatory price auction, and an opportunity-cost system. The results show that compared to the uniform price auction system, the other auction systems can increase the cost-effectiveness of conservation contracting. Competitive bidding can reveal true opportunity costs and can reduce information rents extracted from the government by farmers using private information. The demographics and average bids of these auction types were also analyzed. "Perfect information" in the opportunity-cost offer system has the best performance but is very hard to implement in reality. The results of this research show that the auction is a valuable tool for purchasing conservation contracts in northwestern China, but that in the future, the performance of these auctions should be studied with relaxed model assumptions.

  5. Heat transfer augmentation in double pipe heat exchanger using mechanical turbulators

    NASA Astrophysics Data System (ADS)

    Kamboj, Kushal; Singh, Gurjeet; Sharma, Rohit; Panchal, Dilbagh; Hira, Jaspreet

    2016-05-01

    The work presented here focuses on heat transfer augmentation by means of divergent-convergent spring turbulator (the enhancement device). Aim of the present work is to find such an optimum pitch at which the augmentation in heat transfer is maximum and the amount of power consumption is minimum, so that an economic design can be created with maximum thermal efficiency. So, the concept of pitch variation is introduced, which is defined as the horizontal distance between two consecutive turbulators. It describes that, the lesser is the pitch the more number of turbulators that can be inserted in inner pipe of double pipe heat exchanger, hence more will be the friction factor. This physics increases convective ability of the heat transfer process from the surface of inner pipe. There is a certain limit to which a pitch can be decreased, lesser the pitch the more the pressure drop and friction factor and hence the more will be the pumping power requirement to maintain a desired mass flow rate of hot water. Analysis of thermal factors such as Nusselts number, friction factor, with different pitches of divergent convergent spring turbulators of circular cross-section 15, 10, and 5 cm at Reynolds's number ranging between 9000 < Re < 40,000 is done graphically.

  6. Mechanochemical approach to get layered double hydroxides: Mechanism explore on crystallite growth

    NASA Astrophysics Data System (ADS)

    Zeng, Mei-Gui; Huo, Xiao-Lei; Liu, Su-Qing; Li, Shu-Ping; Li, Xiao-Dong

    2014-02-01

    In this paper, the mechanochemical approach, which includes solid state reactions and hydrothermal treatment, has been proposed to synthesize magnesium-aluminum-layered double hydroxides (Mg-Al-LDHs). Specially, the reaction process of solid state reactions has been explored, and it presents that crystallite growth is the rate-controlling process. The hydrothermal treatment is performed after solid state reactions, on one hand, the crystallinity and monodispersity of final LDHs particles can be improved, on the other hand, such treatment can tailor the particle size efficiently. Furthermore, the relationship between particle size and hydrothermal conditions (time and temperature) has been systematically investigated, which indicates that the particle size and monodispersity can be effectively controlled. The crystallite growth along a-b plane and c-axis has been emphatically discussed, and the results show that under relatively low temperatures such as 100 °C, the gradual growth along c-axis has been found in the range of 48 h, and high temperatures will hider its growth on the contrary. Crystal growth along a-b plane could be accelerated by higher hydrothermal temperature and longer treatment time. Our studies also show that during the hydrothermal treatment, such events as aggregation, disaggregation and particle growth, occur in series or in parallel with time. At last, the Mg-Al-CO3-LDHs samples (synthesized at 100 °C for 24, 36 and 48 h) which were acid activated by HCOOH were used to adsorb fluoride ions present in aqueous solution.

  7. The Mechanism of Double-Strand DNA Break Repair by the Nonhomologous DNA End Joining Pathway

    PubMed Central

    Lieber, Michael R.

    2011-01-01

    Double-strand DNA breaks are common events in eukaryotic cells, and there are two major pathways for repairing them: homologous recombination and nonhomologous DNA end joining (NHEJ). The diverse causes of DSBs result in a diverse chemistry of DNA ends that must be repaired. Across NHEJ evolution, the enzymes of the NHEJ pathway exhibit a remarkable degree of structural tolerance in the range of DNA end substrate configurations upon which they can act. In vertebrate cells, the nuclease, polymerases and ligase of NHEJ are the most mechanistically flexible and multifunctional enzymes in each of their classes. Unlike repair pathways for more defined lesions, NHEJ repair enzymes act iteratively, act in any order, and can function independently of one another at each of the two DNA ends being joined. NHEJ is critical not only for the repair of pathologic DSBs as in chromosomal translocations, but also for the repair of physiologic DSBs created during V(D)J recombination and class switch recombination. Therefore, patients lacking normal NHEJ are not only sensitive to ionizing radiation, but also severely immunodeficient. PMID:20192759

  8. Measuring electrical and mechanical properties of red blood cells with a double optical tweezers

    NASA Astrophysics Data System (ADS)

    Fontes, Adriana; Fernandes, Heloise P.; Barjas-Castro, Maria L.; de Thomaz, André A.; Pozzo, Liliana d. Y.; Barbosa, Luiz C.; Cesar, Carlos L.

    2006-08-01

    The fluid lipid bilayer viscoelastic membrane of red blood cells (RBC) contains antigen glycolproteins and proteins which can interact with antibodies to cause cell agglutination. This is the basis of most of the immunohematologic tests in blood banks and the identification of the antibodies against the erythrocyte antigens is of fundamental importance for transfusional routines. The negative charges of the RBCs creates a repulsive electric (zeta) potential between the cells and prevents their aggregation in the blood stream. The first counterions cloud strongly binded moving together with the RBC is called the compact layer. This report proposes the use of a double optical tweezers for a new procedure for measuring: (1) the apparent membrane viscosity, (2) the cell adhesion, (3) the zeta potential and (4) the compact layer's size of the charges formed around the cell in the electrolytic solution. To measure the membrane viscosity we trapped silica beads strongly attached to agglutinated RBCs and measured the force to slide one RBC over the other as a function of the relative velocity. The RBC adhesion was measured by slowly displacing two RBCs apart until the disagglutination happens. The compact layer's size was measured using the force on the silica bead attached to a single RBC in response to an applied voltage and the zeta potential was obtained by measuring the terminal velocity after releasing the RBC from the optical trap at the last applied voltage. We believe that the methodology here proposed can improve the methods of diagnosis in blood banks.

  9. Mechanical Properties of Double-Layer and Graded Composite Coatings of YSZ Obtained by Atmospheric Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Carpio, Pablo; Rayón, Emilio; Salvador, María Dolores; Lusvarghi, Luca; Sánchez, Enrique

    2016-04-01

    Double-layer and graded composite coatings of yttria-stabilized zirconia were sprayed on metallic substrates by atmospheric plasma spray. The coating architecture was built up by combining two different feedstocks: one micro- and one nanostructured. Microstructural features and mechanical properties (hardness and elastic modulus) of the coatings were determined by FE-SEM microscopy and nanoindentation technique, respectively. Additional adherence and scratch tests were carried out in order to assess the failure mechanisms occurring between the layers comprising the composites. Microstructural inspection of the coatings confirms the two-zone microstructure. This bimodal microstructure which is exclusive of the layer obtained from the nanostructured feedstock negatively affects the mechanical properties of the whole composite. Nanoindentation tests suitably reproduce the evolution of mechanical properties through coatings thickness on the basis of the position and/or amount of nanostructured feedstock used in the depositing layer. Adhesion and scratch tests show the negative effect on the coating adhesion of layer obtained from the nanostructured feedstock when this layer is deposited on the bond coat. Thus, the poor integrity of this layer results in lower normal stresses required to delaminate the coating in the adhesion test as well as minor critical load registered by using the scratch test.

  10. Development of Thread Rolled Anti-Loosening Bolts Based on the Double Thread Mechanism and a Performance Evaluation

    NASA Astrophysics Data System (ADS)

    Takemasu, Teruie; Miyahara, Hiroshi

    It has already been proven that bolt fasteners based on the double thread mechanism have an excellent anti-loosening performance. The purpose of this study is to establish a mass production method for these double thread bolts (DTBs) by thread rolling. The pitch ratio of the coarse thread and the fine thread of the target DTB is set as 2 to 1. A two-die roller with a plunge feed is employed as the rolling method due to its fine processing precision. The roller dies used in the experiments have special grooves on the external surface which follow the same outline as the thread profiles of the DTB. Using these special dies, the DTB can be successfully formed in the same process as single thread bolts. The deformation of a workpiece during rolling is examined, and the examination shows that the formed material smoothly fills the die grooves in each cross section. The rolled DTBs completely pass the loosening test with extremely severe vibration and impact, as specified in NAS3354. The tensile fatigue strength of the rolled DTB is about 100% greater than that of the cutting DTB.

  11. Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

    NASA Astrophysics Data System (ADS)

    Kaassis, Abdessamad Y. A.; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

    2016-06-01

    The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co1.2Zn3.8(OH)8](NO3)2·2H2O (CoZn-NO3), [Ni2Zn3(OH)8](NO3)2·2H2O (NiZn-NO3) and [Zn5(OH)8](NO3)2·2H2O (Zn-NO3). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO3 but when it was reacted with Zn-NO3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an "X" shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO3 and Zn-NO3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO3 and of Val into CoZn-NO3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles.

  12. Studying red blood cell agglutination by measuring electrical and mechanical properties with a double optical tweezers

    NASA Astrophysics Data System (ADS)

    Fontes, Adriana; Fernandes, Heloise P.; de Thomaz, André A.; Barbosa, Luiz C.; Barjas-Castro, Maria L.; Cesar, Carlos L.

    2007-07-01

    The red blood cell (RBC) viscoelastic membrane contains proteins and glycolproteins embedded in, or attached, to a fluid lipid bilayer and are negatively charged, which creates a repulsive electric (zeta) potential between the cells and prevents their aggregation in the blood stream. The basis of the immunohematologic tests is the interaction between antigens and antibodies that causes hemagglutination. The identification of antibodies and antigens is of fundamental importance for the transfusional routine. This agglutination is induced by decreasing the zeta-potential through the introduction of artificial potential substances. This report proposes the use of the optical tweezers to measure the membrane viscosity, the cell adhesion, the zeta-potential and the size of the double layer of charges (CLC) formed around the cell in an electrolytic solution. The adhesion was quantified by slowly displacing two RBCs apart until the disagglutination. The CLC was measured using the force on the bead attached to a single RBC in response to an applied voltage. The zeta-potential was obtained by measuring the terminal velocity after releasing the RBC from the optical trap at the last applied voltage. For the membrane viscosity experiment, we trapped a bead attached to RBCs and measured the force to slide one RBC over the other as a function of the relative velocity. After we tested the methodology, we performed measurements using antibody and potential substances. We observed that this experiment can provide information about cell agglutination that helps to improve the tests usually performed in blood banks. We also believe that this methodology can be applied for measurements of zeta-potentials in other kind of samples.

  13. Kirk effect mechanism in type-II InP /GaAsSb double heterojunction bipolar transistors

    NASA Astrophysics Data System (ADS)

    Tao, N. G.; Bolognesi, C. R.

    2007-09-01

    The Kirk effect mechanism is studied in type-II InP /GaAsSb/InP NpN double heterojunction bipolar transistors (DHBTs) both experimentally and through two-dimensional hydrodynamic numerical simulations. We show that the large valence band discontinuity ΔEV at the GaAsSb-InP base/collector heterojunction does not allow hole injection into the InP collector as is the case in homojunction collectors. Instead, a blocking barrier is electrostatically induced in the base layer at high collector current densities: this barrier increases base recombination and decreases the current gain. We show that tunneling transport must be considered at the base/collector heterojunction and that the induced barrier depends on the base layer doping level—effectively, InP /GaAsSb DHBTs display high-current limitations that are also controlled to some extent by the base doping level.

  14. The NuA4 Core Complex Acetylates Nucleosomal Histone H4 through a Double Recognition Mechanism.

    PubMed

    Xu, Peng; Li, Chengmin; Chen, Zhihong; Jiang, Shuanying; Fan, Shilong; Wang, Jiawei; Dai, Junbiao; Zhu, Ping; Chen, Zhucheng

    2016-09-15

    NuA4 catalyzes the acetylation of nucleosomes at histone H4, which is a well-established epigenetic event, controlling many genomic processes in Saccharomyces cerevisiae. Here we report the crystal structures of the NuA4 core complex and a cryoelectron microscopy structure with the nucleosome. The structures show that the histone-binding pocket of the enzyme is rearranged, suggesting its activation. The enzyme binds the histone tail mainly through the target lysine residue, with a preference for a small residue at the -1 position. The complex engages the nucleosome at the dish face and orients its catalytic pocket close to the H4 tail to achieve selective acetylation. The combined data reveal a space-sequence double recognition mechanism of the histone tails by a modifying enzyme in the context of the nucleosome. PMID:27594449

  15. Identification of shareholder ethics and responsibilities in online reverse auctions for construction projects.

    PubMed

    Hatipkarasulu, Yilmaz; Gill, James H

    2004-04-01

    The increasing number of companies providing internet services and auction tools helped popularize the online reverse auction trend for purchasing commodities and services in the last decade. As a result, a number of owners, both public and private, accepted the online reverse auctions as the bidding technique for their construction projects. Owners, while trying to minimize their costs for construction projects, are also required to address their ethical responsibilities to the shareholders. In the case of online reverse auctions for construction projects, the ethical issues involved in the bidding technique directly reflects on the owner's ethical and social responsibilities to their shareholders. The goal of this paper is to identify the shareholder ethics and responsibilities in online reverse auctions for construction projects by analyzing the ethical issues for the parties involved in the process. The identification of the ethical issues and responsibilities requires clear definition and understanding of professional ethics and the roles of the involved parties. In this paper, first, the concept of professional ethics and social responsibility is described in a general form. To illustrate the ethical issues and responsibilities, a sample case of bidding for a construction project using online reverse auction techniques is presented in which the shareholders were actively involved in questioning the ethical issues. The issues involved in the bidding process and their reflection on the shareholder responsibilities are described and analyzed for each stage of the process. A brief discussion of the overall process is also included to address the general ethical issues involved in online reverse auctions. PMID:15152854

  16. Study of Electrical Conduction Mechanism of Organic Double-Layer Diode Using Electric Field Induced Optical Second Harmonic Generation Measurement.

    PubMed

    Nishi, Shohei; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2016-04-01

    By using electric field induced optical second harmonic generation (EFISHG) and current voltage (I-V) measurements, we studied the electrical transport mechanism of organic double-layer diodes with a structure of Au/N, N'-di-[(1-naphthyl)-N, N'-diphenyl]-(1,1'-biphenyl)-4,4'-diamine (a-NPD)/poly(methyl methacrylate) (PMMA)/indium zinc oxide (IZO). Here the α-NPD is a carrier transport layer and the PMMA is an electrical insulating layer. The current level was very low, but the I-V characteristics showed a rectifying behavior. The EFISHG measurement selectively and directly probed the electric field across the α-NPD layer, and showed that the electric field across the a-NPD layer is completely relaxed owing to the charge accumulation at the a-NPD/PMMA interface in the region V > 0, whereas the carrier accumulation was not significant in the region V < 0. On the basis of these experimental results, we proposed a model of the rectification. Further, by coupling the I-V characteristics with the EFISHG measurement, the I-V characteristics of the diodes were well converted into the current-electric field (I-E) characteristics of the α-NPD layer and the PMMA layer. The I-E characteristics suggested the Schottky-type conduction governs the carrier transport. We conclude that the I-V measurement coupled with the EFISHG measurement is very useful to study carrier transport mechanism of the organic double-layer diodes. PMID:27451633

  17. Double torsion fracture mechanics testing of shales under chemically reactive conditions

    NASA Astrophysics Data System (ADS)

    Chen, X.; Callahan, O. A.; Holder, J. T.; Olson, J. E.; Eichhubl, P.

    2015-12-01

    Fracture properties of shales is vital for applications such as shale and tight gas development, and seal performance of carbon storage reservoirs. We analyze the fracture behavior from samples of Marcellus, Woodford, and Mancos shales using double-torsion (DT) load relaxation fracture tests. The DT test allows the determination of mode-I fracture toughness (KIC), subcritical crack growth index (SCI), and the stress-intensity factor vs crack velocity (K-V) curves. Samples are tested at ambient air and aqueous conditions with variable ionic concentrations of NaCl and CaCl2, and temperatures up to 70 to determine the effects of chemical/environmental conditions on fracture. Under ambient air condition, KIC determined from DT tests is 1.51±0.32, 0.85±0.25, 1.08±0.17 MPam1/2 for Marcellus, Woodford, and Mancos shales, respectively. Tests under water showed considerable change of KIC compared to ambient condition, with 10.6% increase for Marcellus, 36.5% decrease for Woodford, and 6.7% decrease for Mancos shales. SCI under ambient air condition is between 56 and 80 for the shales tested. The presence of water results in a significant reduction of the SCI from 70% to 85% compared to air condition. Tests under chemically reactive solutions are currently being performed with temperature control. K-V curves under ambient air conditions are linear with stable SCI throughout the load-relaxation period. However, tests conducted under water result in an initial cracking period with SCI values comparable to ambient air tests, which then gradually transition into stable but significantly lower SCI values of 10-20. The non-linear K-V curves reveal that crack propagation in shales is initially limited by the transport of chemical agents due to their low permeability. Only after the initial cracking do interactions at the crack tip lead to cracking controlled by faster stress corrosion reactions. The decrease of SCI in water indicates higher crack propagation velocity due to

  18. Evidence for a near-resonant charge transfer mechanism for double-stranded peptide nucleic acid.

    PubMed

    Venkatramani, Ravindra; Davis, Kathryn L; Wierzbinski, Emil; Bezer, Silvia; Balaeff, Alexander; Keinan, Shahar; Paul, Amit; Kocsis, Laura; Beratan, David N; Achim, Catalina; Waldeck, David H

    2011-01-12

    We present evidence for a near-resonant mechanism of charge transfer in short peptide nucleic acid (PNA) duplexes obtained through electrochemical, STM break junction (STM-BJ), and computational studies. A seven base pair (7-bp) PNA duplex with the sequence (TA)(3)-(XY)-(TA)(3) was studied, in which XY is a complementary nucleobase pair. The experiments showed that the heterogeneous charge transfer rate constant (k(0)) and the single-molecule conductance (σ) correlate with the oxidation potential of the purine base in the XY base pair. The electrochemical measurements showed that the enhancement of k(0) is independent, within experimental error, of which of the two PNA strands contains the purine base of the XY base pair. 7-bp PNA duplexes with one or two GC base pairs had similar measured k(0) and conductance values. While a simple superexchange model, previously used to rationalize charge transfer in single stranded PNA (Paul et al. J. Am. Chem. Soc. 2009, 131, 6498-6507), describes some of the experimental observations, the model does not explain the absence of an enhancement in the experimental k(0) and σ upon increasing the G content in the duplexes from one to two. Moreover, the superexchange model is not consistent with other studies (Paul et al. J. Phys. Chem. B 2010, 114, 14140), that showed a hopping charge transport mechanism is likely important for PNA duplexes longer than seven base pairs. A quantitative computational analysis shows that a near-resonant charge transfer regime, wherein a mix of superexchange and hopping mechanisms are expected to coexist, can rationalize all of the experimental results. PMID:21141966

  19. Immunological mechanisms contributing to the double burden of diabetes and intracellular bacterial infections

    PubMed Central

    Hodgson, Kelly; Morris, Jodie; Bridson, Tahnee; Govan, Brenda; Rush, Catherine; Ketheesan, Natkunam

    2015-01-01

    Diabetes has been recognized as an important risk factor for a variety of intracellular bacterial infections, but research into the dysregulated immune mechanisms contributing to the impaired host–pathogen interactions is in its infancy. Diabetes is characterized by a chronic state of low-grade inflammation due to activation of pro-inflammatory mediators and increased formation of advanced glycation end products. Increased oxidative stress also exacerbates the chronic inflammatory processes observed in diabetes. The reduced phagocytic and antibacterial activity of neutrophils and macrophages provides an intracellular niche for the pathogen to replicate. Phagocytic and antibacterial dysfunction may be mediated directly through altered glucose metabolism and oxidative stress. Furthermore, impaired activation of natural killer cells contributes to decreased levels of interferon-γ, required for promoting macrophage antibacterial mechanisms. Together with impaired dendritic cell function, this impedes timely activation of adaptive immune responses. Increased intracellular oxidation of antigen-presenting cells in individuals with diabetes alters the cytokine profile generated and the subsequent balance of T-cell immunity. The establishment of acute intracellular bacterial infections in the diabetic host is associated with impaired T-cell-mediated immune responses. Concomitant to the greater intracellular bacterial burden and potential cumulative effect of chronic inflammatory processes, late hyper-inflammatory cytokine responses are often observed in individuals with diabetes, contributing to systemic pathology. The convergence of intracellular bacterial infections and diabetes poses new challenges for immunologists, providing the impetus for multidisciplinary research. PMID:25262977

  20. A double-ratchet mechanism of transcription elongation and its control

    NASA Astrophysics Data System (ADS)

    Ruckenstein, Andrei

    2005-03-01

    Transcription, the process by which the genetic information encoded in DNA is transferred into RNA, is the first step in gene expression and it is the step at which most regulation occurs. A detailed understanding of the structural and mechanistic aspects of each step of transcription (initiation, elongation, termination and regulation) is one of the holy grails of biology. Here we characterize the motion of RNA polymerase (RNAP), the multi-subunit molecular motor that carries out the transcription process, during the elongation stage. We argue that during elongation RNAP moves by a complex Brownian ratchet mechanism in which the translocation along DNA and the binding of nucleotides into RNAP's catalytic center are coupled to a fluctuating internal degree of freedom associated with a protein sub-unit (the F-bridge) of RNAP. More precisely, the model is defined by a set of kinetic equations^ describing the competition for the catalytic site between an incoming nucleotide, the 3'-end of RNA, and the F-bridge which in its bent conformation blocks the active center. An important aspect of the model is the incorporation of the three ``active'' processes describing (i) the ejection of bound nucleotides from the active center through steric clashes with either the F-bridge in its bent conformation or with the 3'-end of RNA; and (ii) the forward translocation induced by bending of the F-bridge pushing against the 3'-end of RNA. The ``active'' processes do not imply a ``power stroke'' mechanism since the energy driving them is purely thermal. Indeed the model displays a route by which the system uses thermal fluctuations to control the rate, processivity and fidelity of transcription already before the irreversible chemical incorporation step. Moreover, the model qualitatively explains many aspects of both bio-chemicalootnotetextBar-Nahum, G., Epshtein, V., Ruckenstein, A.E., Rafikov, R., Mustaev, A., and Nudler, E. A ratchet mechanism of transcription elongation and its

  1. Competitive bidding for health insurance contracts: lessons from the online HMO auctions.

    PubMed

    Gupta, Alok; Parente, Stephen T; Sanyal, Pallab

    2012-12-01

    Healthcare is an important social and economic component of modern society, and the effective use of information technology in this industry is critical to its success. As health insurance premiums continue to rise, competitive bidding may be useful in generating stronger price competition and lower premium costs for employers and possibly, government agencies. In this paper, we assess an endeavor by several Fortune 500 companies to reduce healthcare procurement costs for their employees by having HMOs compete in open electronic auctions. Although the auctions were successful in generating significant cost savings for the companies in the first year, i.e., 1999, they failed to replicate the success and were eventually discontinued after two more years. Over the past decade since the failed auction experiment, effective utilization of information technologies have led to significant advances in the design of complex electronic markets. Using this knowledge, and data from the auctions, we point out several shortcomings of the auction design that, we believe, led to the discontinuation of the market after three years. Based on our analysis, we propose several actionable recommendations that policy makers can use to design a sustainable electronic market for procuring health insurance.

  2. 75 FR 56533 - Wireless Telecommunications Bureau Postpones Auction of 218-219 MHz Service and Phase II 220 MHz...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-16

    ... COMMISSION Wireless Telecommunications Bureau Postpones Auction of 218-219 MHz Service and Phase II 220 MHz... document announces the postponement of Auction 89. FOR FURTHER INFORMATION CONTACT: Wireless... related documents are also available on the Internet at the Commission's Web site:...

  3. Electronic Reverse Auctions: Integrating an E-Sourcing Tool into a Sales and Purchasing Cross-Course Negotiation Project

    ERIC Educational Resources Information Center

    Williams, Jacqueline A.; Dobie, Kathryn

    2011-01-01

    Electronic reverse auctions are increasingly being used by firms to improve firm financial and operational performance. The described teaching innovation serves as a model for introducing electronic reverse auctions as a central element in a comprehensive negotiation exercise involving sales management and purchasing management students. Results…

  4. 30 CFR 585.308 - How will BOEM conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and RUE grants? 585.308 Section 585.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Obtaining Row Grants and Rue Grants § 585.308 How will BOEM conduct an auction for ROW grants and RUE grants... to comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The...

  5. 30 CFR 585.308 - How will BOEM conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and RUE grants? 585.308 Section 585.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Obtaining Row Grants and Rue Grants § 585.308 How will BOEM conduct an auction for ROW grants and RUE grants... to comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The...

  6. 30 CFR 585.308 - How will BOEM conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and RUE grants? 585.308 Section 585.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Obtaining Row Grants and Rue Grants § 585.308 How will BOEM conduct an auction for ROW grants and RUE grants... to comment; and (2) Conduct a competitive auction for issuing the ROW grant or RUE grant. The...

  7. 7 CFR 29.75b - Display of baled flue-cured tobacco on auction warehouse floors in designated markets.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Display of baled flue-cured tobacco on auction... AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations Mandatory Inspection § 29.75b Display of baled flue-cured tobacco on auction warehouse floors in designated...

  8. 7 CFR 29.75b - Display of baled flue-cured tobacco on auction warehouse floors in designated markets.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Display of baled flue-cured tobacco on auction... AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations Mandatory Inspection § 29.75b Display of baled flue-cured tobacco on auction warehouse floors in designated...

  9. 7 CFR 29.75a - Display of burley tobacco on auction warehouse floors in designated markets.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Display of burley tobacco on auction warehouse floors... COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations Mandatory Inspection § 29.75a Display of burley tobacco on auction warehouse floors in designated markets. (a)(1) Each...

  10. 7 CFR 29.75b - Display of baled flue-cured tobacco on auction warehouse floors in designated markets.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Display of baled flue-cured tobacco on auction... AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations Mandatory Inspection § 29.75b Display of baled flue-cured tobacco on auction warehouse floors in designated...

  11. 7 CFR 29.75a - Display of burley tobacco on auction warehouse floors in designated markets.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Display of burley tobacco on auction warehouse floors... COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations Mandatory Inspection § 29.75a Display of burley tobacco on auction warehouse floors in designated markets. (a)(1) Each...

  12. 7 CFR 29.75a - Display of burley tobacco on auction warehouse floors in designated markets.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Display of burley tobacco on auction warehouse floors... COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations Mandatory Inspection § 29.75a Display of burley tobacco on auction warehouse floors in designated markets. (a)(1) Each...

  13. 78 FR 21355 - Tribal Mobility Fund Phase I Auction Scheduled for October 24, 2013; Comment Sought on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... Mobility Fund Phase I, 77 FR 14012. Petitions for designation as an ETC should be filed in WC Docket No. 09..., 76 FR 73830, November 29, 2011 and 76 FR 81562, December 28, 2011. Auction 902 will award one-time... COMMISSION Tribal Mobility Fund Phase I Auction Scheduled for October 24, 2013; Comment Sought on...

  14. 77 FR 7152 - Mobility Fund Phase I Auction Scheduled for September 27, 2012; Comment Sought on Competitive...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... the Commission in the USF/ICC Transformation Order, 76 FR 73830, November 29, 2011 and 76 FR 81562... COMMISSION Mobility Fund Phase I Auction Scheduled for September 27, 2012; Comment Sought on Competitive... Wireline Competition Bureaus announce a reverse auction to award $300 million in one-time Mobility...

  15. 77 FR 11115 - Mobility Fund Phase I Auction Limited Extension of Deadlines for Comments and Reply Comments on...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... released the Auction 901 Comment Public Notice, 77 FR 7152, February 10, 2012, which seeks comment on... Commission in the USF/ICC Transformation Order, 76 FR 73830, November 29, 2011 and 76 FR 81562, December 28... COMMISSION Mobility Fund Phase I Auction Limited Extension of Deadlines for Comments and Reply Comments...

  16. 75 FR 8703 - Auction of Lower and Upper Paging Bands Licenses Scheduled for May 25, 2010; Notice and Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-25

    ... referred to as the red light rule, that implement the Commission's ] obligations under the Debt Collection... Public Notice, 74 FR 67221, December 18, 2009. i. Licenses to be Offered in Auction 87 2. Auction 87 will... disclosures that may violate 47 CFR 1.2105(c), particularly in light of the limited information procedures...

  17. Quantum Mechanical Effects on the Threshold Voltage of Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Hu, Guang-Xi; Liu, Ran; Qiu, Zhi-Jun; Wang, Ling-Li; Tang, Ting-Ao

    2010-03-01

    A model for a metal-oxide-semiconductor field-effect transistor (MOSFET) with a double gate (DG) is developed. Quantum mechanical effects on the threshold voltage (VTH) are modeled and investigated analytically. The analytic model shows how VTH is increased with quantum mechanical effect. The model is applicable to both symmetric DG (SDG) and asymmetric DG (ADG) nMOSFETs, and is also applicable to both doped and undoped DG nMOSFETs. The analytic results are verified by comparing with the results obtained from simulations using Schred, and good agreement is observed. The VTH of an ADG nMOSFET will shift more than that of an SDG nMOSFET, and the VTH of a DG transistor with (110)-silicon (Si) orientation will shift more than that of a DG transistor with (100)-Si orientation. When the silicon thickness tsi < 3 nm, the VTH shift will be significant, and one should be careful in the use of an extremely thin silicon body. When the body doping density (NA) is not high (<1018 cm-3), the VTH shift is almost the same for different NA. When NA > 1018 cm-3, the higher the NA, the more the VTH shift.

  18. Sorption characteristics and mechanisms of oxyanions and oxyhalides having different molecular properties on Mg/Al layered double hydroxide nanoparticles.

    PubMed

    Goh, Kok-Hui; Lim, Teik-Thye; Banas, Agnieszka; Dong, Zhiling

    2010-07-15

    The sorption ability of fast-coprecipitated and hydrothermally-treated Mg/Al layered double hydroxide nanoparticles (FCHT-LDH) for various oxyhalides and oxyanions was evaluated. Interactions of oxyhalide such as monovalent bromate or oxyanions such as divalent chromate and divalent vanadate with FCHT-LDH were investigated using a combination of macroscopic (batch sorption/desorption studies and electrophoretic mobility (EM) measurements) and microscopic techniques (CHNS/O, XRD, FTIR, XPS, and EXAFS analyses). The sorption studies on various oxyanions and oxyhalides suggested that their sorption characteristics on FCHT-LDH were largely governed by their ionic potentials and molecular structures. Oxyanions which have ionic potentials higher than 7 nm(-1) were found to be more readily sorbed by FCHT-LDH than oxyhalides with ionic potentials lower than 5 nm(-1). The results obtained also demonstrated that trigonal pyramid oxyhalides showed a lower degree of specificity for FCHT-LDH than the tetrahedral coordinated oxyanions. From the macroscopic and microscopic studies, monovalent oxyhalide sorption on FCHT-LDH was postulated to occur mainly via anion exchange mechanism with subsequent formation of outer-sphere surface complexes. For polyvalent oxyanion sorption on FCHT-LDH, the mechanisms were possibly associated with both anion exchange and ligand exchange reactions, resulting in the coexistence of outer-sphere and inner-sphere surface complexes. PMID:20399010

  19. Double-diffusive convection as a mechanism for transferring heat and mass within the Salton Sea geothermal brine

    SciTech Connect

    Fournier, Robert O.

    1988-01-01

    H. C. Helgeson noted in 1968 that the salinity of the brine in the geothermal reservoir within the Salton Sea geothermal system generally increases from the top to the bottom and from the center to the sides. He also noted that pressure measurements at perforations in cased wells seemed to indicate that the formation fluids at the depths of production have a specific density about equal to 1, and that hot concentrated brines apparently exist in pressure equilibrium with comparatively cold dilute pore waters in the surrounding rocks. Since 1968 there have been no published reports that dispute these observations. However, a very high heat flux through the top of the system seems to require a substantial component of convective transfer of heat beneath an impermeable cap, whereas the apparent salinity gradient with depth seems to require little or no free convection of brine. This paradox may be resolved if double-diffusive convection is the main process that controls the depth-temperature-salinity relations. Such convection provides a mechanism for transferring heat from the bottom to the top of the hydrothermal system while maintaining vertical and horizontal salinity gradients—densities remaining close to unity. In 1981, Griffiths showed experimentally that layered double-diffusive convection cells may develop in porous media when hot saline waters underlie more dilute cooler waters. However, nagging questions remain about whether fluid densities within the Salton Sea geothermal system really adjust to unity in response to changing temperature and salinity at depths greater than about 1 km. The State 2-14 well, the Salton Sea Scientific Drill Hole, has provided one high-quality data point for a depth interval of 1,865-1,877 m, where the temperature is about 305º C. The calculated density of the pre-flashed reservoir fluid sampled from that depth is 1.0008 ± 0.0023.

  20. Physical contact influences how much people pay at celebrity auctions

    PubMed Central

    Newman, George E.; Bloom, Paul

    2014-01-01

    Contagion is a form of magical thinking in which people believe that a person’s immaterial qualities or essence can be transferred to an object through physical contact. Here we investigate how a belief in contagion influences the sale of celebrity memorabilia. Using data from three high-profile estate auctions, we find that people’s expectations about the amount of physical contact between the object and the celebrity positively predicts the final bids for items that belonged to well-liked individuals (e.g., John F. Kennedy) and negatively predicts final bids for items that belonged to disliked individuals (e.g., Bernard Madoff). A follow-up experiment further suggests that these effects are driven by contagion beliefs: when asked to bid on a sweater owned by a well-liked celebrity, participants report that they would pay substantially less if it was sterilized before they received it. However, sterilization increases the amount they would pay for a sweater owned by a disliked celebrity. These studies suggest that magical thinking may still have effects in contemporary Western societies and they provide some unique demonstrations of contagion effects on real-world purchase decisions. PMID:24567388

  1. Physical contact influences how much people pay at celebrity auctions.

    PubMed

    Newman, George E; Bloom, Paul

    2014-03-11

    Contagion is a form of magical thinking in which people believe that a person's immaterial qualities or essence can be transferred to an object through physical contact. Here we investigate how a belief in contagion influences the sale of celebrity memorabilia. Using data from three high-profile estate auctions, we find that people's expectations about the amount of physical contact between the object and the celebrity positively predicts the final bids for items that belonged to well-liked individuals (e.g., John F. Kennedy) and negatively predicts final bids for items that belonged to disliked individuals (e.g., Bernard Madoff). A follow-up experiment further suggests that these effects are driven by contagion beliefs: when asked to bid on a sweater owned by a well-liked celebrity, participants report that they would pay substantially less if it was sterilized before they received it. However, sterilization increases the amount they would pay for a sweater owned by a disliked celebrity. These studies suggest that magical thinking may still have effects in contemporary Western societies and they provide some unique demonstrations of contagion effects on real-world purchase decisions. PMID:24567388

  2. The directed self-assembly of nanostructures: Electric pressure, dipole, double layer and cracking mechanisms

    NASA Astrophysics Data System (ADS)

    Salac, David

    2007-12-01

    This dissertation presents investigations into the self-assembly of a wide number of material systems. This research introduces the concept that electric fields oriented in the plane of a thin polymer film will induce surface instabilities which grow to form structures. This experimental result indicates that large scale fabrication of nano- and micro-structures in a polymer film can be affectively achieved in an easy to construct and maintain setup. Electrostatic interactions have also been presented as a possible controlling mechanism in forming nanometer sized structure in molecularly thin film. A theoretical and computational investigation presented here indicates that the use of dipolar multilayer system combined with a substrate containing embedded electrodes is capable of fabricating patterns which would be difficult to obtain otherwise. It was observed that subsequent layers in a multilayer system will undergo layer-by-layer alignment and feature size reduction. The result has been applied to the ''molecular car'' concept, by which molecules are able to migrate on a surface due to externally controllable electric field patterns. The scaling and ordering of metallic nanoclusters on semiconductor substrates has been explored computationally. Numerical techniques were implemented to calculate the total electrostatic and van der Waals energies for systems containing multiple disks. Observations show that interactions in charge clouds beneath the metallic disks led to an electrostatic repulsive force. Attraction was observed by the van der Waals energy. An energy barrier past which disk coalescence will not occur was observed. This has applications in the development of large-scale nanodot systems which require precise control over both dot location and size. Finally, this dissertation presents results of systematic investigation of nanocracking in thin films using numerical techniques. Using a level-set method to describe an arbitrary crack in a heterogeneous

  3. Spiral of Hatred: Social Effects in Buyer-Seller Cross-Comments Left on Internet Auctions

    NASA Astrophysics Data System (ADS)

    Nielek, Radoslaw; Wawer, Aleksander; Wierzbicki, Adam

    An auction platform is a dynamic environment where a rich variety of social effects can be observed. Most of those effects remain unnoticed or even hidden to ordinary users. The in-depth studies of such effects should allow us to identify and understand the key factors influencing users’ behaviour. The material collected from the biggest Polish auction house has been analyzed. NLP algorithms were applied to extract sentiment-related content from collected comments. Emotional distance between negative, neutral and positive comments has been calculated. The obtained results confirm the existence of the spiral-of-hatred effect but also indicate that much more complex patterns of mutual relations between sellers and buyers exist. The last section contains a several suggestions which can prove useful to improve trustworthiness of users’ reports and security of an auction platform in general.

  4. Bidding process in online auctions and winning strategy: Rate equation approach.

    PubMed

    Yang, I; Kahng, B

    2006-06-01

    Online auctions have expanded rapidly over the last decade and have become a fascinating new type of business or commercial transaction in this digital era. Here we introduce a master equation for the bidding process that takes place in online auctions. We find that the number of distinct bidders who bid k times up to the tth bidding progresses, called the k-frequent bidder, seems to scale as n(k)(t) approximately tk(-2.4). The successfully transmitted bidding rate by the k-frequent bidder is likely to scale as q(k)(t) approximately k(-1.4), independent of t for large t. This theoretical prediction is close to empirical data. These results imply that bidding at the last moment is a rational and effective strategy to win in an eBay auction. PMID:16907028

  5. Bidding process in online auctions and winning strategy: Rate equation approach

    NASA Astrophysics Data System (ADS)

    Yang, I.; Kahng, B.

    2006-06-01

    Online auctions have expanded rapidly over the last decade and have become a fascinating new type of business or commercial transaction in this digital era. Here we introduce a master equation for the bidding process that takes place in online auctions. We find that the number of distinct bidders who bid k times up to the t th bidding progresses, called the k -frequent bidder, seems to scale as nk(t)˜tk-2.4 . The successfully transmitted bidding rate by the k -frequent bidder is likely to scale as qk(t)˜k-1.4 , independent of t for large t . This theoretical prediction is close to empirical data. These results imply that bidding at the last moment is a rational and effective strategy to win in an eBay auction.

  6. Assays for DNA double-strand break repair by microhomology-based end-joining repair mechanisms.

    PubMed

    Kostyrko, Kaja; Mermod, Nicolas

    2016-04-01

    DNA double stranded breaks (DSBs) are one of the most deleterious types of DNA lesions. The main pathways responsible for repairing these breaks in eukaryotic cells are homologous recombination (HR) and non-homologous end-joining (NHEJ). However, a third group of still poorly characterized DSB repair pathways, collectively termed microhomology-mediated end-joining (MMEJ), relies on short homologies for the end-joining process. Here, we constructed GFP reporter assays to characterize and distinguish MMEJ variant pathways, namely the simple MMEJ and the DNA synthesis-dependent (SD)-MMEJ mechanisms. Transfection of these assay vectors in Chinese hamster ovary (CHO) cells and characterization of the repaired DNA sequences indicated that while simple MMEJ is able to mediate relatively efficient DSB repair if longer microhomologies are present, the majority of DSBs were repaired using the highly error-prone SD-MMEJ pathway. To validate the involvement of DNA synthesis in the repair process, siRNA knock-down of different genes proposed to play a role in MMEJ were performed, revealing that the knock-down of DNA polymerase θ inhibited DNA end resection and repair through simple MMEJ, thus favoring the other repair pathway. Overall, we conclude that this approach provides a convenient assay to study MMEJ-related DNA repair pathways.

  7. Study of the negative ion extraction mechanism from a double-ion plasma in negative ion sources

    SciTech Connect

    Goto, I.; Nishioka, S.; Hatayama, A.; Miyamoto, K.

    2015-04-08

    We have developed a 2D3V-PIC model of the extraction region, aiming to clarify the basic extraction mechanism of H{sup −} ions from the double-ion plasma in H{sup −} negative ion sources. The result shows the same tendency of the H{sup −} ion density n{sub H{sup −}} as that observed in the experiments, i.e.,n{sub H{sup −}} in the upstream region away from the plasma meniscus (H{sup −} emitting surface) has been reduced by applying the extraction voltage. At the same time, relatively slow temporal oscillation of the electric potential compared with the electron plasma frequency has been observed in the extraction region. Results of the systematic study using a 1D3V-PIC model with the uniform magnetic field confirm the result that the electrostatic oscillation is identified to be lower hybrid wave. The effect of this oscillation on the H{sup −} transport will be studied in the future.

  8. Stimulating somatosensory psychophysics: a double-blind, sham-controlled study of the neurobiological mechanisms of tDCS

    PubMed Central

    Hanley, Claire J.; Tommerdahl, Mark; McGonigle, David J.

    2015-01-01

    The neuromodulation technique transcranial direct current stimulation (tDCS) is thought to produce its effects on behavior by altering cortical excitability. Although the mechanisms underlying the observed effects are thought to rely on the balance of excitatory and inhibitory neurotransmission, the physiological principles of the technique are not completely understood. In this study, we examine the influence of tDCS on vibrotactile adaptation, using a simple amplitude discrimination paradigm that has been shown to exhibit modifications in performance due to changes in inhibitory neurotransmission. Double-blind tDCS (Anodal/Sham) of 1 mA was delivered for 600 s to electrodes positioned in a somatosensory/contralateral orbit montage. Stimulation was applied as part of a pre/post design, between blocks of the behavioral tasks. In accordance with previous work, results obtained before the application of tDCS indicated that amplitude discrimination thresholds were significantly worsened during adaptation trials, compared to those achieved at baseline. However, tDCS failed to modify amplitude discrimination performance. Using a Bayesian approach, this finding was revealed to constitute substantial evidence for the null hypothesis. The failure of DC stimulation to alter vibrotactile adaptation thresholds is discussed in the context of several factors that may have confounded the induction of changes in cortical plasticity. PMID:26500499

  9. A high security double lock and key mechanism in HUH relaxases controls oriT-processing for plasmid conjugation

    PubMed Central

    Carballeira, José Daniel; González-Pérez, Blanca; Moncalián, Gabriel; de la Cruz, Fernando

    2014-01-01

    Relaxases act as DNA selection sieves in conjugative plasmid transfer. Most plasmid relaxases belong to the HUH endonuclease family. TrwC, the relaxase of plasmid R388, is the prototype of the HUH relaxase family, which also includes TraI of plasmid F. In this article we demonstrate that TrwC processes its target nic-site by means of a highly secure double lock and key mechanism. It is controlled both by TrwC–DNA intermolecular interactions and by intramolecular DNA interactions between several nic nucleotides. The sequence specificity map of the interaction between TrwC and DNA was determined by systematic mutagenesis using degenerate oligonucleotide libraries. The specificity map reveals the minimal nic sequence requirements for R388-based conjugation. Some nic-site sequence variants were still able to form the U-turn shape at the nic-site necessary for TrwC processing, as observed by X-ray crystallography. Moreover, purified TrwC relaxase effectively cleaved ssDNA as well as dsDNA substrates containing these mutant sequences. Since TrwC is able to catalyze DNA integration in a nic-site-containing DNA molecule, characterization of nic-site functionally active sequence variants should improve the search quality of potential target sequences for relaxase-mediated integration in any target genome. PMID:25123661

  10. In vitro MRI of biodegradable hybrid (iron oxide/polycaprolactone) magnetic nanoparticles prepared via modified double emulsion evaporation mechanism.

    PubMed

    Ahmed, Naveed; Ahmad, Nasir M; Fessi, Hatem; Elaissari, Abdelhamid

    2015-06-01

    Hybrid magnetic particles are being applied in biomedical field for various aims. One of such aim is use of magnetic particles for diagnostic purposes especially in imaging mechanisms. In vitro magnetic resonance imaging of biodegradable hybrid (iron oxide/polycaprolactone) magnetic nanoparticles is carried out. Hybrid magnetic nanoparticles were prepared by encapsulation of iron oxide nanoparticles (IONPs) in polycaprolactone (PCL) via modified double emulsion evaporation technique. Both the IONPs and hybrid nanoparticles were characterized for their sizes, zeta potential, microscopic, thermogravimetric, and magnetism. Prepared particles were investigated for T1 and T2 weighted enhancement of contrast in vitro in water. A comparison of the prepared particles was done with commercially available Gadolinium for the contrast efficiency in MRI. Results showed the prepared particles exhibited nanosize range, good morphology and superparamagnetic character. The enhancement in the MRI contrast of the prepared particles was observed and found to depend on type of the prepared particles. Comparison of the MRI contrast of the prepared particles with the commercial Gadolinium suggests their usefulness as T2 contrast agent.

  11. Scaling of volume to surface ratio and doubling time in growing unicellular organisms: Do cells appear quantum-mechanical systems?

    NASA Astrophysics Data System (ADS)

    Atanasov, Atanas Todorov

    2014-10-01

    The scaling of physical and biological characteristics of the living organisms is a basic method for searching of new biophysical laws. In series of previous studies the author showed that in Poikilotherms, Mammals and Aves, the volume to surface ratio V×S-1 (m) of organisms is proportional to their generation time Tgt(s) via growth rate v (m s-1): V×S-1 = vgr×Tr. The power and the correlation coefficients are near to 1.0. Aim of this study is: i) to prove with experimental data the validity of the above equation for Unicellular organisms and ii) to show that perhaps, the cells are quantum-mechanical systems. The data for body mass M (kg), density ρ (kg/m3), minimum and maximum doubling time Tdt (s) for 50 unicellular organisms are assembled from scientific sources, and the computer program `Statistics' is used for calculations. In result i) the analytical relationship from type: V×S-1 = 4.46ṡ10-11×Tdt was found, where vgr = 4.46×10-11 m/s and ii) it is shown that the products between cell mass M, cell length expressed by V/S ratio and growth rate vgr satisfied the Heisenberg uncertainty principle i.e. the inequalities V/S×M×vgr>h/2π and Tdt×M×vgr2>h/2π are valid, where h= 6.626×10-34 Jṡs is the Planck constant. This rise the question: do cells appear quantum-mechanical systems?

  12. Scaling of volume to surface ratio and doubling time in growing unicellular organisms: Do cells appear quantum-mechanical systems?

    SciTech Connect

    Atanasov, Atanas Todorov

    2014-10-06

    The scaling of physical and biological characteristics of the living organisms is a basic method for searching of new biophysical laws. In series of previous studies the author showed that in Poikilotherms, Mammals and Aves, the volume to surface ratio V×S{sup −1} (m) of organisms is proportional to their generation time T{sub gt}(s) via growth rate v (m s{sup −1}): V×S{sup −1} = v{sub gr}×T{sup r}. The power and the correlation coefficients are near to 1.0. Aim of this study is: i) to prove with experimental data the validity of the above equation for Unicellular organisms and ii) to show that perhaps, the cells are quantum-mechanical systems. The data for body mass M (kg), density ρ (kg/m{sup 3}), minimum and maximum doubling time T{sub dt} (s) for 50 unicellular organisms are assembled from scientific sources, and the computer program ‘Statistics’ is used for calculations. In result i) the analytical relationship from type: V×S{sup −1} = 4.46⋅10{sup −11}×T{sub dt} was found, where v{sub gr} = 4.46×10{sup −11} m/s and ii) it is shown that the products between cell mass M, cell length expressed by V/S ratio and growth rate v{sub gr} satisfied the Heisenberg uncertainty principle i.e. the inequalities V/S×M×v{sub gr}>h/2π and T{sub dt}×M×v{sub gr}{sup 2}>h/2π are valid, where h= 6.626×10{sup −34} J⋅s is the Planck constant. This rise the question: do cells appear quantum-mechanical systems?.

  13. Double Mantle Plume Upwelling—A Possible Formation Mechanism of Beta Plateau and Devana Chasma,Venus

    NASA Astrophysics Data System (ADS)

    Ding, N.

    2009-12-01

    Ning Ding,Zuoxun Zeng,China University of Geosciences,Wuhan,430074,China NingDing.eagle@gmail.com Introduction:Venus represents a‘one plate planet’[1],and the uplift,fractures and volcanism in Beta Regio on Venus are considered to be formed by lithosphere uplift driven by a hot plume[2]. Based on the double peaking saddle landform,we suggest the tectonic pattern of double mantle plume upwelling to interpret the formation mechanism of Beta Plateau and Devana Chasma.We take a physical modeling to validate this possibility. Model:There is no ductile shear in Venus[3],so we use quartz sands to simulate the crust of Venus.We use two wood stickes 1.5cm in diameter rising from the rubber canvas slowly and straight till about half of the model,then falling down slowly and straight.The base is a hard rubber plate,in the center of which,there are two holes 3cm in diameter,and the distance between them is 5cm.The holes are covered by rubber canvas.We use the quartz sands in colours of white, red and black with particle size of 70 mess as the model materials. Result:Fig.1:At the beginning of the wood stickes upwelling,only fine radial cracks are formed above the upwelling from central to outside.With the upwelling continue,surface energy of the fine radial cracks increase and make the cracks unstable,finally,the fine radial cracks connect each other and form a fracture zone.And then the two mantle plume downwelling,the fracture zone is developed to form a chasma at the end. Fig.2:The four profiles all form reverse faults outside and normal faults inside.But the difference is the faults in the middle of the chasma goes deeper than others.It is the pattern of Beta Plateau where the tectonic rising is cut by Devana Chasma zone in the topographic features. Fig.3:From the tow fig., we can see two points similar:a.the elevation is high and distribution area is large around the area of two upwelling and it is high around the area of chasma,but the distribution area is small

  14. 25 CFR 215.4 - Leases to be sold at public auction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Leases to be sold at public auction. 215.4 Section 215.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING... provided in the regulations in this part, no lead and zinc mining lease under this part of restricted...

  15. 25 CFR 215.4 - Leases to be sold at public auction.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Leases to be sold at public auction. 215.4 Section 215.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING... provided in the regulations in this part, no lead and zinc mining lease under this part of restricted...

  16. 31 CFR 356.20 - How does the Treasury determine auction awards?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... hundredth of a whole percentage point, for example, 17.13%. (b) Determining the interest rate for new note and bond issues. We set the interest rate at a 1/8 of one percent increment. If a Treasury inflation-protected securities auction results in a negative or zero yield, the interest rate will be set at zero,...

  17. 77 FR 9655 - Mobility Fund Phase I Auction Updated List of Potentially Eligible Census Blocks

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-17

    ..., 77 FR 7152, February 10, 2012, comments are due on or before February 24, 2012. Reply comments are... Public Notice, 77 FR 7152, February 10, 2012, all filings in response to the notice must refer to AU... program requirements in the Auction 901 (Mobility Fund Phase I) Comment Public Notice, 77 FR...

  18. 31 CFR 356.33 - Does the Treasury have any discretion in the auction process?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Does the Treasury have any discretion... CIRCULAR, PUBLIC DEBT SERIES NO. 1-93) Miscellaneous Provisions § 356.33 Does the Treasury have any discretion in the auction process? (a) We have the discretion to: (1) Accept, reject, or refuse to...

  19. 25 CFR 215.4 - Leases to be sold at public auction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Leases to be sold at public auction. 215.4 Section 215.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING... provided in the regulations in this part, no lead and zinc mining lease under this part of restricted...

  20. 77 FR 69933 - Expanding the Economic and Innovation Opportunities of Spectrum Through Incentive Auctions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-21

    ... Electronic Filing of Documents in Rulemaking Proceedings, 63 FR 24121 (1998). Electronic Filers: Comments may... less complex software than a multiple round auction and thus be easier for the Commission to implement... optimization software to try to find the most efficient way of clearing a specified amount of...

  1. 47 CFR 27.604 - Limitation on licenses won at auction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Limitation on licenses won at auction. 27.604 Section 27.604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Guard Band A and B Blocks (757-758/787-788 MHz and...

  2. 47 CFR 27.604 - Limitation on licenses won at auction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Limitation on licenses won at auction. 27.604 Section 27.604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Guard Band A and B Blocks (757-758/787-788 MHz and...

  3. 27 CFR 31.63 - Agents, auctioneers, brokers, etc., acting on behalf of others.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Exemptions and Exceptions Persons Who Are Not Dealers in Liquors Or Beer § 31.63 Agents, auctioneers, brokers... account of those activities. Those persons, who have no property rights in the liquors sold, may make... beer who merely receive and transmit to a wholesale dealer orders for liquors or beer to be...

  4. 40 CFR 97.421 - Recordation of TR NOX Annual allowance allocations and auction results.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Recordation of TR NOX Annual allowance... TRADING PROGRAMS TR NOX Annual Trading Program § 97.421 Recordation of TR NOX Annual allowance allocations and auction results. (a) By November 7, 2011, the Administrator will record in each TR NOX...

  5. 77 FR 38061 - Mobility Fund Phase I Auction Supplemental Short-Form Instructions and Other Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-26

    ... Notice, 77 FR 32092, May 31, 2012, the Bureaus provided general instructions for completing FCC Form 180... COMMISSION Mobility Fund Phase I Auction Supplemental Short-Form Instructions and Other Information AGENCY... Telecommunications and Wireline ] Competition Bureaus provide supplemental filing instructions for the Mobility...

  6. 25 CFR 215.4 - Leases to be sold at public auction.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Leases to be sold at public auction. 215.4 Section 215.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEAD AND ZINC MINING... provided in the regulations in this part, no lead and zinc mining lease under this part of restricted...

  7. 49 CFR Appendix F to Part 599 - Salvage Auction Certification Form

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Salvage Auction Certification Form F Appendix F to Part 599 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... CONSUMER ASSISTANCE TO RECYCLE AND SAVE ACT PROGRAM Pt. 599, App. F Appendix F to Part 599—Salvage...

  8. 49 CFR Appendix F to Part 599 - Salvage Auction Certification Form

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Salvage Auction Certification Form F Appendix F to Part 599 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... CONSUMER ASSISTANCE TO RECYCLE AND SAVE ACT PROGRAM Pt. 599, App. F Appendix F to Part 599—Salvage...

  9. 49 CFR Appendix F to Part 599 - Salvage Auction Certification Form

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Salvage Auction Certification Form F Appendix F to Part 599 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... CONSUMER ASSISTANCE TO RECYCLE AND SAVE ACT PROGRAM Pt. 599, App. F Appendix F to Part 599—Salvage...

  10. Teaching Undergraduate Money and Banking: T-Bill Auctions and Stock Market Models

    ERIC Educational Resources Information Center

    Saros, Daniel E.

    2009-01-01

    The author offers innovative approaches to 3 topics that are typically only briefly mentioned (if at all) in money and banking courses. The first topic is a Treasury bill auction experiment in which students have an opportunity to participate directly. The results from a class of 14 money and banking students are used to explain how an instructor…

  11. See Art History in a New Light: Have an Art Auction

    ERIC Educational Resources Information Center

    Benter, Doris J.

    2008-01-01

    At Portledge School in Locust Valley, New York, ninth graders in their upper school study art history for one semester. The visual arts department has created a vigorous new syllabus culminating in an hour-long mock art auction. The department selects several art movements (e.g., Post-Impressionism, Cubism, Abstract Expressionism, Social Realism,…

  12. 49 CFR Appendix F to Part 599 - Salvage Auction Certification Form

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Salvage Auction Certification Form F Appendix F to Part 599 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... CONSUMER ASSISTANCE TO RECYCLE AND SAVE ACT PROGRAM Pt. 599, App. F Appendix F to Part 599—Salvage...

  13. 49 CFR Appendix F to Part 599 - Salvage Auction Cerification Form

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Salvage Auction Cerification Form F Appendix F to Part 599 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY... CONSUMER ASSISTANCE TO RECYCLE AND SAVE ACT PROGRAM Pt. 599, App. F Appendix F to Part 599—Salvage...

  14. Probing the Mechanism of the Double C—H (De)Activation Route of a Ru-Based Olefin Metathesis Catalyst

    NASA Astrophysics Data System (ADS)

    Poater, Albert; Cavallo, Luigi

    A theoretical study of a double C—H activation mechanism that deactivates a family of second generation Ru-based catalysts is presented. DFT calculations are used to rationalize the complex mechanistic pathway from the starting precatalyst to the experimentally characterized decomposition products. In particular, we show that all the intermediates proposed by Grubbs and coworkers are indeed possible intermediates in the deactivation pathway, although the sequence of steps is somewhat different

  15. The influence of an online auction's product price and e-retailer reputation on consumers' perception, attitude, and behavioral intention.

    PubMed

    Wu, Wann-Yih; Huang, Po-Ching; Fu, Chen-Su

    2011-06-01

    Online auctions combine the conventional auction model with information technology. However, information asymmetry within such auctions causes risks and uncertainties that influence consumer purchase intentions. In this study, a 2 (product price: high vs. low) × 2 (e-retailer reputation: high vs. low) experimental design was used to understand whether the product price and e-retailer reputation will influence consumers' perceived risk, attitude toward the website and purchase intention. The results of this study indicate that perceived risk negatively influences consumer attitude toward the website and online purchase intention, while consumer attitude toward the website positively influences purchase intention. Moreover, involvement moderates the influence of product price and e-retailer reputation only on social risk but does not have a significant effect on consumer attitude toward the website. This study contributes to a more comprehensive understanding of online auction users' behavior. Finally, the managerial implications, limitations and future research directions are also provided. PMID:21332721

  16. The influence of an online auction's product price and e-retailer reputation on consumers' perception, attitude, and behavioral intention.

    PubMed

    Wu, Wann-Yih; Huang, Po-Ching; Fu, Chen-Su

    2011-06-01

    Online auctions combine the conventional auction model with information technology. However, information asymmetry within such auctions causes risks and uncertainties that influence consumer purchase intentions. In this study, a 2 (product price: high vs. low) × 2 (e-retailer reputation: high vs. low) experimental design was used to understand whether the product price and e-retailer reputation will influence consumers' perceived risk, attitude toward the website and purchase intention. The results of this study indicate that perceived risk negatively influences consumer attitude toward the website and online purchase intention, while consumer attitude toward the website positively influences purchase intention. Moreover, involvement moderates the influence of product price and e-retailer reputation only on social risk but does not have a significant effect on consumer attitude toward the website. This study contributes to a more comprehensive understanding of online auction users' behavior. Finally, the managerial implications, limitations and future research directions are also provided.

  17. Equilibrium Strategy and Population-Size Effects in Lowest Unique Bid Auctions

    NASA Astrophysics Data System (ADS)

    Pigolotti, Simone; Bernhardsson, Sebastian; Juul, Jeppe; Galster, Gorm; Vivo, Pierpaolo

    2012-02-01

    In lowest unique bid auctions, N players bid for an item. The winner is whoever places the lowest bid, provided that it is also unique. We use a grand canonical approach to derive an analytical expression for the equilibrium distribution of strategies. We then study the properties of the solution as a function of the mean number of players, and compare them with a large data set of internet auctions. The theory agrees with the data with striking accuracy for small population-size N, while for larger N a qualitatively different distribution is observed. We interpret this result as the emergence of two different regimes, one in which adaptation is feasible and one in which it is not. Our results question the actual possibility of a large population to adapt and find the optimal strategy when participating in a collective game.

  18. Collective induction without cooperation? Learning and knowledge transfer in cooperative groups and competitive auctions.

    PubMed

    Maciejovsky, Boris; Budescu, David V

    2007-05-01

    There is strong evidence that groups perform better than individuals do on intellective tasks with demonstrably correct solutions. Typically, these studies assume that group members share common goals. The authors extend this line of research by replacing standard face-to-face group interactions with competitive auctions, allowing for conflicting individual incentives. In a series of studies involving the well-known Wason selection task, they demonstrate that competitive auctions induce learning effects equally impressive as those of standard group interactions, and they uncover specific and general knowledge transfers from these institutions to new reasoning problems. The authors identify payoff feedback and information pooling as the driving factors underlying these findings, and they explain these factors within the theoretical framework of collective induction.

  19. A Q-Learning-Based Supplier Bidding Strategy in Electricity Auction Market

    NASA Astrophysics Data System (ADS)

    Xiong, Gaofeng; Hashiyama, Tomonori; Okuma, Shigeru

    One of the most important issues for power suppliers in the deregulated electric industry is how to bid into the electricity auction market to satisfy their profit-maximizing goals. Based on the Q-Learning algorithm, this paper presents a novel supplier bidding strategy to maximize supplier’s profit in the long run. In this approach, the supplier bidding strategy is viewed as one kind of stochastic optimal control problem and each supplier can learn from experience. A competitive day-ahead electricity auction market with hourly bids is assumed here, where no supplier possesses the market power and all suppliers winning the market are paid based on their own bid prices. The dynamics and the incomplete information of the market are considered. The impact of suppliers’ strategic bidding on the market price is analyzed. Agent-based simulations are presented. The simulation results show the feasibility of the proposed bidding strategy.

  20. A Supplier Bidding Strategy Through Q-Learning Algorithm in Electricity Auction Markets

    NASA Astrophysics Data System (ADS)

    Xiong, Gaofeng; Hashiyama, Tomonori; Okuma, Shigeru

    One of the most important issues for power suppliers in the deregulated electric industry is how to bid into the electricity auction market to satisfy their profit-maximizing goals. Based on the Q-Learning algorithm, this paper presents a novel supplier bidding strategy to maximize supplier’s profit in the long run. In this approach, the supplier bidding strategy is viewed as a kind of stochastic optimal control problem and each supplier can learn from experience. A competitive day-ahead electricity auction market with hourly bids is assumed here, where no supplier possesses the market power. The dynamics and the incomplete information of the market are considered. The impacts of suppliers’ strategic bidding on the market price are analyzed under uniform pricing rule and discriminatory pricing rule. Agent-based simulations are presented. The simulation results show the feasibility of the proposed bidding strategy.

  1. Biased Random-Key Genetic Algorithms for the Winner Determination Problem in Combinatorial Auctions.

    PubMed

    de Andrade, Carlos Eduardo; Toso, Rodrigo Franco; Resende, Mauricio G C; Miyazawa, Flávio Keidi

    2015-01-01

    In this paper we address the problem of picking a subset of bids in a general combinatorial auction so as to maximize the overall profit using the first-price model. This winner determination problem assumes that a single bidding round is held to determine both the winners and prices to be paid. We introduce six variants of biased random-key genetic algorithms for this problem. Three of them use a novel initialization technique that makes use of solutions of intermediate linear programming relaxations of an exact mixed integer linear programming model as initial chromosomes of the population. An experimental evaluation compares the effectiveness of the proposed algorithms with the standard mixed linear integer programming formulation, a specialized exact algorithm, and the best-performing heuristics proposed for this problem. The proposed algorithms are competitive and offer strong results, mainly for large-scale auctions.

  2. Research at the auction block: Problems for the fair benefits approach to international research.

    PubMed

    London, Alex John; Zollman, Kevin J S

    2010-01-01

    The "fair benefits" approach to international research is designed to produce results that all can agree are fair without taking a stand on divisive questions of justice. But its appealing veneer of collaboration masks ambiguities at both a conceptual and an operational level. An attempt to put it into practice would look a lot like an auction, leaving little reason to think the outcomes will satisfy even minimal conditions of fairness.

  3. Improving the secrecy rate by turning foes to allies: An auction scheme

    NASA Astrophysics Data System (ADS)

    Ma, Ya-Yan; Wang, Bao-Yun

    2015-09-01

    Security against eavesdroppers is a critical issue in cognitive radio networks (CRNs). In this paper, a scenario consisting of one primary pair and multiple secondary pairs is considered. The secondary transmitters (STs) work in half-duplex mode and they are potential eavesdroppers on the primary transmission unless they are allowed to simultaneously transmit with the primary transmitter (PT). A modified second-price sealed-bid auction scheme is employed to model the interaction between the PT and STs. With the proposed auction scheme, the hostile relationship between the PT and STs is transformed into a cooperative relationship. An iterative algorithm based on the max-min criteria is proposed to find the optimal bidding power of the STs for an access chance in the presence of multiple eavesdroppers. Numerical results show that the proposed auction scheme not only improves the PT’s security but also increases the access opportunities of the STs. Project supported by the National Natural Science Foundation of China (Grant Nos. 61271232 and 61372126) and the University Postgraduate Research and Innovation Project in Jiangsu Province, China (Grant No. CXZZ12-0472).

  4. Clean air, clear market. Making emissions trading work: The role of a computer-assisted auction

    SciTech Connect

    Bartels, C.W.; Marron, D.B.; Lipsky, M.I.

    1993-06-15

    Creating a new commodity presents the chance to develop new markets in which to trade it. In many cases, existing markets can be adapted easily; in other cases it proves worthwhile to develop new forms that reflect special characteristics of the commodity and those who trade it. In the case of the sulfur dioxide (SO[sub 2]) emission allowances created by the Clean Air Act Amendments of 1990, a number of standard market forms already have been adopted. While these will prove useful for handling some transactions, a new Market Clearing Auction (MCA) offers buyers and sellers a centralized marketplace for trading SO[sub 2] emission allowances. The MCA, which was developed by the brokerage firm Cantor Fitzgerald, is a computer-assisted [open quotes]smart[close quotes] auction designed to replicate the outcome of an efficient market in emission allowances, and accepts bids and offers for any possible combination of allowances. Orders can be submitted for streams of allowances. Orders can be submitted for streams of allowances covering more than one year. The auction then determines the combination of bids and offers that maximizes the gains from trades in the market, and establishes uniform market clearing prices for each allowance issue (1995, 1996, and so on). Once executed, trades are settled on a cash-forward basis; that is, allowances are delivered and payments are made at future dates.

  5. Bulk-wave and guided-wave photoacoustic evaluation of the mechanical properties of aluminum/silicon nitride double-layer thin films.

    PubMed

    Zhang, Feifei; Krishnaswamy, Sridhar; Lilley, Carmen M

    2006-12-01

    The development of devices made of micro- and nano-structured thin film materials has resulted in the need for advanced measurement techniques to characterize their mechanical properties. Photoacoustic techniques, which use pulsed laser irradiation to nondestructively induce very high frequency ultrasound in a test object via rapid thermal expansion, are suitable for nondestructive and non-contact evaluation of thin films. In this paper, we compare two photoacoustic techniques to characterize the mechanical parameters of edge-supported aluminum and silicon nitride double-layer thin films. The elastic properties and residual stresses in such films affect their mechanical performance. In a first set of experiments, a femtosecond transient pump-probe technique is used to investigate the Young's moduli of the aluminum and silicon nitride layers by launching ultra-high frequency bulk acoustic waves in the films. The measured transient signals are compared with simulated transient thermoelastic signals in multi-layer structures, and the elastic moduli are determined. Independent pump-probe tests on silicon substrate-supported region and unsupported region are in good agreement. In a second set of experiments, dispersion curves of the A(0) mode of the Lamb waves that propagate along the unsupported films are measured using a broadband photoacoustic guided-wave method. The residual stresses and flexural rigidities for the same set of double-layer membranes are determined from these dispersion curves. Comparisons of the results obtained by the two photoacoustic techniques are made and discussed.

  6. Double Your Pleasure, Double Your Funds.

    ERIC Educational Resources Information Center

    McCall, Miles; Sitton, Bob

    1999-01-01

    Discusses a variety of fun activities that college and universities can develop as alumni fund-raising events: a golf tournament; scholarship auctions (silent, on-the-spot, live televised, and live); charitable raffles; duck dashes; themed banquets; and a tuition raffle. (MSE)

  7. Car-Parrinello molecular dynamics study of the intramolecular vibrational mode-sensitive double proton-transfer mechanisms in porphycene.

    PubMed

    Walewski, Łukasz; Waluk, Jacek; Lesyng, Bogdan

    2010-02-18

    Car-Parrinello molecular dynamics simulations were carried out to help interpret proton-transfer processes observed experimentally in porphycene under thermodynamic equilibrium conditions (NVT ensemble) as well as during selective, nonequilibrium vibrational excitations of the molecular scaffold (NVE ensemble). In the NVT ensemble, the population of the trans form in the gas phase at 300 K is 96.5%, and of the cis-1 form is 3.5%, in agreement with experimental data. Approximately 70% of the proton-transfer events are asynchronous double proton transfers. According to the high resolution simulation data they consist of two single transfer events that rapidly take place one after the other. The average time-period between the two consecutive jumps is 220 fs. The gas phase reaction rate estimate at 300 K is 3.6 ps, which is comparable to experimentally determined rates. The NVE ensemble nonequilibrium ab initio MD simulations, which correspond to selective vibrational excitations of the molecular scaffold generated with high resolution laser spectroscopy techniques, exhibit an enhancing property of the 182 cm(-1) vibrational mode and an inhibiting property of the 114 cm(-1) one. Both of them influence the proton-transfer rate, in qualitative agreement with experimental findings. Our ab initio simulations provide new predictions regarding the influence of double-mode vibrational excitations on proton-transfer processes. They can help in setting up future programmable spectroscopic experiments for the proton-transfer translocations. PMID:20099852

  8. Double-stranded cleavage of pBR322 by a diiron complex via a "hydrolytic" mechanism.

    PubMed Central

    Schnaith, L M; Hanson, R S; Que, L

    1994-01-01

    Treatment of plasmid pBR322 with Fe2-(HPTB)(OH)(NO3)4(HPTB = N,N,N',N'-tetrakis(2-benzimidazolylmethyl)-2-hydroxy-1,3-diaminopr opane) and H2O2 or O2 and a reductant (dithiothreitol or ascorbate) results in double-stranded cleavage of the plasmid. The linearization of supercoiled pBR322 by this complex is not inhibited by hydroxyl radical scavengers. On the other hand, the linearized pBR322 is efficiently religated by T4 DNA ligase, and the presence of 3'-OH and 5'-OPO3 ends is corroborated by 3'- and 5'-end-labeling studies. These observations indicate that cleavage results from hydrolysis of the DNA-phosphate backbone, which is proposed to occur by nucleophilic attack of the bound peroxide on the phosphodiester. Double-stranded cleavage by the Fe2(HPTB)(OH)(NO3)4/H2O2 adduct preferentially occurs between bp 3489 and 3485 of pBR322. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8290564

  9. A new class of intermediate phases in non-crystalline films based on a confluent double percolation mechanism

    NASA Astrophysics Data System (ADS)

    Lucovsky, Gerald; Phillips, James C.

    2007-11-01

    Recent research results have suggested that double percolation processes play a significant role in the formation of intermediate phases (IPs) in non-crystalline thin films. One class of IP windows, involving competitive double percolation, occurs in binary AsxSe1-x and GexSe1-x alloys and in the pseudo-binary AsxGexSe1-2x alloy. This IP window occurs over an 8-12% composition range. Transitions that define the IP window in the Ge-Se alloys involve a competition between the elimination of compliant local bonding dimer groups, e.g. Ge-Se-Se-Ge, at the expense of an increasing fraction of rigid local bonding monomer groups, e.g. Ge-Se-Ge. Compliant monomer group bonding defines the first window transition for an average number of bonding constraints/atom, nc = 3; the second transition from rigid to stressed rigid occurs when the compliant monomer concentration drops below a concentration for percolation. A second class of IPs with significantly narrower composition windows, ~1 to at most 3%, is proposed to explain experimentally determined IPs in chalcogenide alloys with halogen dopants; e.g. a-Ge0.25Se0.77-xIx, where the IP window width is ~1%. We suggest that this narrow window is determined by a confluent coherent double percolation process that includes (i) broken bond-bending constraints that minimize local bond strain, and (ii) a percolation pathway based on a second and complementary local bonding group. However, this second class of IPs is not supported by theory and modeling as yet, and as such our designation of this class of IPs must be regarded as more speculative. On the other had, it is significant that at least two other alloy systems, Ge2Se2Te5 and pseudo-ternary Hf, Zr and Ti Si oxynitrides, display narrow regimes where bond constraint counting indicates local strain suppression, and where a second and larger bonding arrangement is present at the percolation limit.

  10. Double-Network Hydrogel with Tunable Mechanical Performance and Biocompatibility for the Fabrication of Stem Cells-Encapsulated Fibers and 3D Assemble.

    PubMed

    Liang, Zhe; Liu, Chenguang; Li, Lili; Xu, Peidi; Luo, Guoan; Ding, Mingyu; Liang, Qionglin

    2016-01-01

    Fabrication of cell-encapsulated fibers could greatly contribute to tissue engineering and regenerative medicine. However, existing methods suffered from not only unavoidability of cell damaging conditions and/or sophisticated equipment, but also unavailability of proper materials to satisfy both mechanical and biological expectations. In this work, a simple method is proposed to prepare cell-encapsulated fibers with tunable mechanical strength and stretching behavior as well as diameter and microstructure. The hydrogel fibers are made from optimal combination of alginate and poly(N-iso-propylacrylamide)-poly(ethylene glycol), characteristics of double-network hydrogel, with enough stiffness and flexibility to create a variety of three dimensional structures like parallel helical and different knots without crack. Furthermore, such hydrogel fibers exhibit better compatibility as indicated by the viability, proliferation and expression of pluripotency markers of embryonic stem cells encapsulated after 4-day culture. The double-network hydrogel possesses specific quick responses to either of alginate lyase, EDTA or lower environmental temperature which facilitate the optional degradation of fibers or fibrous assemblies to release the cells encapsulated for subsequent assay or treatment. PMID:27628933

  11. Double-Network Hydrogel with Tunable Mechanical Performance and Biocompatibility for the Fabrication of Stem Cells-Encapsulated Fibers and 3D Assemble

    PubMed Central

    Liang, Zhe; Liu, Chenguang; Li, Lili; Xu, Peidi; Luo, Guoan; Ding, Mingyu; Liang, Qionglin

    2016-01-01

    Fabrication of cell-encapsulated fibers could greatly contribute to tissue engineering and regenerative medicine. However, existing methods suffered from not only unavoidability of cell damaging conditions and/or sophisticated equipment, but also unavailability of proper materials to satisfy both mechanical and biological expectations. In this work, a simple method is proposed to prepare cell-encapsulated fibers with tunable mechanical strength and stretching behavior as well as diameter and microstructure. The hydrogel fibers are made from optimal combination of alginate and poly(N-iso-propylacrylamide)-poly(ethylene glycol), characteristics of double-network hydrogel, with enough stiffness and flexibility to create a variety of three dimensional structures like parallel helical and different knots without crack. Furthermore, such hydrogel fibers exhibit better compatibility as indicated by the viability, proliferation and expression of pluripotency markers of embryonic stem cells encapsulated after 4-day culture. The double-network hydrogel possesses specific quick responses to either of alginate lyase, EDTA or lower environmental temperature which facilitate the optional degradation of fibers or fibrous assemblies to release the cells encapsulated for subsequent assay or treatment. PMID:27628933

  12. Modeling effects of gas bubbles on the mechanical behaviors of Ag/Bi-2212 round wires using a double cantilever beam bridge model

    NASA Astrophysics Data System (ADS)

    Lu, Yurong; Wang, Zhongtong; Yong, Huadong; Zhou, Youhe

    2016-07-01

    Due to the larger current-carrying property, Bi2Sr2CaCu2Ox (Bi2212) superconductors have a great potential application in high field magnet. Bi2212 superconducting material can be fabricated as an isotropic round wire. However, there is 30% void space in the wire, such as gas bubbles. The void space has a larger influence on the property of the wire. In this paper, we will study the effect of gas bubble on the fracture behavior. Based on the double cantilever beam model and critical state theory, the mechanical behavior of Bi2212 wire is studied for decreasing field. Two different damage mechanisms are discussed using the strain energy release rate and strain of bridge. The results show that the large gas bubble can increase the strain of bridge. The central filaments with gas bubble are easier to be damaged than the edge filaments with gas bubble.

  13. The mechanical properties and cytotoxicity of cell-laden double-network hydrogels based on photocrosslinkable gelatin and gellan gum biomacromolecules.

    PubMed

    Shin, Hyeongho; Olsen, Bradley D; Khademhosseini, Ali

    2012-04-01

    A major goal in the application of hydrogels for tissue engineering scaffolds, especially for load-bearing tissues such as cartilage, is to develop hydrogels with high mechanical strength. In this study, a double-network (DN) strategy was used to engineer strong hydrogels that can encapsulate cells. We improved upon previously studied double-network (DN) hydrogels by using a processing condition compatible with cell survival. The DN hydrogels were created by a two-step photocrosslinking using gellan gum methacrylate (GGMA) for the rigid and brittle first network, and gelatin methacrylamide (GelMA) for the soft and ductile second network. We controlled the degree of methacrylation of each polymer so that they obtain relevant mechanical properties as each network. The DN was formed by photocrosslinking the GGMA, diffusing GelMA into the first network, and photocrosslinking the GelMA to form the second network. The formation of the DN was examined by diffusion tests of the large GelMA molecules into the GGMA network, the resulting enhancement in the mechanical properties, and the difference in mechanical properties between GGMA/GelMA single networks (SN) and DNs. The resulting DN hydrogels exhibited the compressive failure stress of up to 6.9 MPa, which approaches the strength of cartilage. It was found that there is an optimal range of the crosslink density of the second network for high strength of DN hydrogels. DN hydrogels with a higher mass ratio of GelMA to GGMA exhibited higher strength, which shows promise in developing even stronger DN hydrogels in the future. Three dimensional (3D) encapsulation of NIH-3T3 fibroblasts and the following viability test showed the cell-compatibility of the DN formation process. Given the high strength and the ability to encapsulate cells, the DN hydrogels made from photocrosslinkable macromolecules could be useful for the regeneration of load-bearing tissues.

  14. Towards an improved prediction of the free radical scavenging potency of flavonoids: the significance of double PCET mechanisms.

    PubMed

    Amić, Ana; Marković, Zoran; Dimitrić Marković, Jasmina M; Stepanić, Višnja; Lučić, Bono; Amić, Dragan

    2014-01-01

    The 1H(+)/1e(-) and 2H(+)/2e(-) proton-coupled electron transfer (PCET) processes of free radical scavenging by flavonoids were theoretically studied for aqueous and lipid environments using the PM6 and PM7 methods. The results reported here indicate that the significant contribution of the second PCET mechanism, resulting in the formation of a quinone/quinone methide, effectively discriminates the active from inactive flavonoids. The predictive potency of descriptors related to the energetics of second PCET mechanisms (the second O-H bond dissociation enthalpy (BDE2) related to hydrogen atom transfer (HAT) mechanism, and the second electron transfer enthalpy (ETE2) related to sequential proton loss electron transfer (SPLET) mechanism) are superior to the currently used indices, which are related to the first 1H(+)/1e(-) processes, and could serve as primary descriptors in development of the QSAR (quantitative structure-activity relationships) of flavonoids.

  15. The impact of product information and trials on demand for smokeless tobacco and cigarettes: Evidence from experimental auctions

    PubMed Central

    Rousu, Matthew C.; O'Connor, Richard; Thrasher, James F; June, Kristie; Bansal-Travers, Maansi; Pitcavage, James

    2014-01-01

    Introduction Epidemiological and toxicological evidence suggests lower risk of smokeless tobacco (ST) products compared to cigarettes. Less is known, however, about consumer perceptions and use of novel forms of ST, including snus and dissolvable tobacco. Methods In this study, we conducted in-person experimental auctions in Buffalo, NY, Columbia, SC, and Selinsgrove, PA with 571 smokers to test the impact of information and product trials on smokers’ preferences. Auctions were conducted between November 2010-November 2011. Results We found no evidence of an impact of product trials on demand in our auctions. Anti-ST information increased demand for cigarettes when presented alone, but when presented with Pro-ST information it decreased demand for cigarettes. It did not decrease demand for ST products. Anti-smoking information increased demand for ST products, but did not affect cigarette demand. Conclusions These findings suggest that credible and effective communications about tobacco harm reduction should reinforce the negative effects of smoking. PMID:24321456

  16. Underlying mechanisms for normal heat transport in one-dimensional anharmonic oscillator systems with a double-well interparticle interaction

    NASA Astrophysics Data System (ADS)

    Xiong, Daxing

    2016-04-01

    Previous studies have suggested a crossover from superdiffusive to normal heat transport in one-dimensional (1D) anharmonic oscillator systems with a double-well type interatomic interaction like V(ξ )=-{ξ2}/2+{ξ4}/4 , when the system temperature is varied. In order to better understand this unusual manner of thermal transport, here we perform a direct dynamics simulation to examine how the spreading processes of the three physical quantities, i.e. the heat, the total energy and the momentum, would depend on temperature. We find three main points that are worth noting. (i) The crossover from superdiffusive to normal heat transport is well verified from a new perspective of heat spread. (ii) The spreading of the total energy is found to be very distinct from heat diffusion, especially under some temperature regimes, energy is strongly localized, while heat can be superdiffusive. So one should take care to derive a general connection between the heat conduction and energy diffusion. (iii) In a narrow range of temperatures, the spreading of momentum implies clear unusual non-ballistic behaviors; however, such unusual transport of momentum cannot be directly related to the normal transport of heat. An analysis of phonon spectra suggests that one should also take the effects of phonon softening into account. All of these results may provide insights into establishing the connection between the macroscopic heat transport and the underlying dynamics in 1D systems.

  17. Central mechanisms of controlled-release metoprolol in migraine: a double-blind, placebo-controlled study.

    PubMed

    Siniatchkin, M; Andrasik, F; Kropp, P; Niederberger, U; Strenge, H; Averkina, N; Lindner, V; Stephani, U; Gerber, W-D

    2007-09-01

    beta-Blockers are widely used in the prophylaxis of migraine and have been described as very effective drugs in many studies. Some investigators have demonstrated that the clinical improvement of migraine corresponds to the normalization of the contingent negative variation (CNV), a slow cortical potential measuring cortical information processing. However, most of these studies have contained a variety of methodological pitfalls, which we attempted to address in the current study. Twenty patients suffering from migraine without aura were randomly divided into two groups. The groups were treated either with controlled-release metoprolol or placebo for 3 months, using a double-blind design. Twice before and once after each month of the treatment the CNV was recorded. After 3 months, a significant reduction of migraine frequency, duration and intensity was demonstrated for the metoprolol compared with the placebo group. The CNV was characterized by a marked reduction of the amplitude of the total CNV and postimperative negative variation and normalization of the eartly CNV habituation following treatment. Therefore, metoprolol may exert its prophylactic effect in migraine through the influence on cortical information processing and excitability represented by the CNV. PMID:17680819

  18. A Winner Determination Algorithm for Combinatorial Auctions Based on Hybrid Artificial Fish Swarm Algorithm

    NASA Astrophysics Data System (ADS)

    Zheng, Genrang; Lin, ZhengChun

    The problem of winner determination in combinatorial auctions is a hotspot electronic business, and a NP hard problem. A Hybrid Artificial Fish Swarm Algorithm(HAFSA), which is combined with First Suite Heuristic Algorithm (FSHA) and Artificial Fish Swarm Algorithm (AFSA), is proposed to solve the problem after probing it base on the theories of AFSA. Experiment results show that the HAFSA is a rapidly and efficient algorithm for The problem of winner determining. Compared with Ant colony Optimization Algorithm, it has a good performance with broad and prosperous application.

  19. Double space with double line

    SciTech Connect

    Cheltsov, I A

    2004-10-31

    For a singular double cover of P{sup 3} ramified in a sextic with double line, its birational maps into Fano 3-folds with canonical singularities, elliptic fibrations, and fibrations on surfaces of Kodaira dimension zero are described.

  20. Double space with double line

    NASA Astrophysics Data System (ADS)

    Cheltsov, I. A.

    2004-10-01

    For a singular double cover of \\mathbb P^3 ramified in a sextic with double line, its birational maps into Fano 3-folds with canonical singularities, elliptic fibrations, and fibrations on surfaces of Kodaira dimension zero are described.

  1. Direct electron-impact mechanism of excitation of mercury monobromide in a double-pulse dielectric-barrier-discharge HgBr lamp

    NASA Astrophysics Data System (ADS)

    Datsyuk, V. V.; Izmailov, I. A.; Naumov, V. V.; Kochelap, V. A.

    2016-08-01

    In a nonequlibrium plasma of a gas-discharge HgBr lamp, the terminal electronic state of the HgBr(B-X) radiative transition with a peak wavelength of 502 nm remains populated for a relatively long time and is repeatedly excited to the B state in collisions with plasma electrons. This transfer of the HgBr molecules from the ground state X to the excited state B is the main mechanism of formation of the light-emitting molecules especially when the lamp is excited by double current pulses. According to our simulations, due to the electron-induced transitions between HgBr(X) and HgBr(B), the output characteristics of the DBD lamp operating in a double-pulse regime are better than those of the lamp operating in a single-pulse regime. In the considered case, the peak power is calculated to increase by a factor of about 2 and the lamp efficiency increases by about 50%.

  2. Direct electron-impact mechanism of excitation of mercury monobromide in a double-pulse dielectric-barrier-discharge HgBr lamp

    NASA Astrophysics Data System (ADS)

    Datsyuk, V. V.; Izmailov, I. A.; Naumov, V. V.; Kochelap, V. A.

    2016-08-01

    In a nonequlibrium plasma of a gas-discharge HgBr lamp, the terminal electronic state of the HgBr(B–X) radiative transition with a peak wavelength of 502 nm remains populated for a relatively long time and is repeatedly excited to the B state in collisions with plasma electrons. This transfer of the HgBr molecules from the ground state X to the excited state B is the main mechanism of formation of the light-emitting molecules especially when the lamp is excited by double current pulses. According to our simulations, due to the electron-induced transitions between HgBr(X) and HgBr(B), the output characteristics of the DBD lamp operating in a double-pulse regime are better than those of the lamp operating in a single-pulse regime. In the considered case, the peak power is calculated to increase by a factor of about 2 and the lamp efficiency increases by about 50%.

  3. Study of laser-plasma interaction using a physics-based model for understanding the physical mechanism of double-pulse effect in nanosecond laser ablation

    SciTech Connect

    Wu Benxin; Zhou Yun; Forsman, Andrew

    2009-12-21

    This paper studies the double-pulse effect in high-intensity ({>=}{approx}GW/cm{sup 2}) nanosecond (ns) laser ablation, which refers to the significant material removal rate enhancement for ablation by two ns laser pulses (often separated by a delay time of {approx}10 to 100 ns). The early-stage interaction of the second laser pulse with the plasma plume created by the first pulse is very important for understanding the physical mechanism of the double pulse effect. However, the plasma properties in the early stage (during a laser pulse or within 20 to 30 ns after the completion of the pulse) are very difficult to measure experimentally. In this letter, a physics-based predictive model is used as the investigation tool, which was previously verified based on experiments on plasma properties in the late stage, which are relatively easy to measure. The study shows that the second laser pulse does not directly strike the target condensed phase. Instead, it mainly interacts with the plasma plume created by the first laser pulse, heats and accelerates the ablated material in the plume lingering above the target surface.

  4. [Double teeth].

    PubMed

    Schuurs, A H B; van Loveren, C

    2002-04-01

    Double teeth are not really rare, but it is still enigmatic why and how they develop. Based upon the clinical, morphological and anatomical appearance and the number of teeth in mouths with double teeth, the double teeth are labelled as products of 'fusion' and 'clefting', but the criteria to attach such etiological names are lacking. It is assumed that heredity is involved in the development of double teeth. Therefore it is attempted to explain why only one of a homozygotic twin had a double tooth. PMID:11982209

  5. Analysis of interface formation mechanism in GaN double-polarity selective-area growth by metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Kuze, Kenta; Osumi, Noriyuki; Fujita, Yohei; Inoue, Yoku; Nakano, Takayuki

    2016-05-01

    The fabrication of quasi-phase-matching (QPM) crystals by selective-area growth on the two asymmetrically polar surfaces of GaN is examined. We attempted the fabrication of GaN-QPM crystals by one-time growth using a carbon mask. For GaN double-polarity selective-area growth (DP-SAG), we investigated the effect of varied nitriding times of the Al2O3 templates patterned with the carbon mask. We optimized the nitriding conditions for the DP-SAG process, and evaluated the substrate fabricated by the optimized DP-SAG process. In addition, we examined the interface formation mechanism of DP-GaN fabricated by GaN DP-SAG process. We determined that it is possible to fabricate DP-GaN with a sharp interface by optimizing the growth conditions.

  6. Dissolution kinetics and mechanism of Mg-Al layered double hydroxides: a simple approach to describe drug release in acid media.

    PubMed

    Parello, Mara L; Rojas, Ricardo; Giacomelli, Carla E

    2010-11-01

    Layered double hydroxides (LDHs) weathering in acidic media is one of the main features that affects their applications in drug delivery systems. In this work, the dissolution kinetics of biocompatible Mg-Al LDHs was studied at different initial pH values and solid concentrations using a simple and fast experimental method that coupled flow injection analysis and amperometric detection. A carbonate intercalated sample was used to determine the controlling step of the process and the dissolution mechanism. Finally, the study was extended to an ibuprofen intercalated LDH. The obtained results showed that the weathering process was mainly controlled by the exposed area and surface reactivity of LDHs particles. The dissolution mechanism at the particle surface was described in two steps: fast formation of surface reactive sites by hydroxyl group protonation and slow detachment of metal ions from surface. At strongly acidic conditions, the reaction rate was pH dependent due to the equilibrium between protonated (active) and deprotonated (inactive) hydroxyl groups. On the other hand, at mildly acidic conditions, the dissolution behavior was also ruled by the equilibrium attained between the particle surface reactive sites and the dissolved species. LDHs solubility and dissolution rate presented strong dependence with the interlayer anion. The ibuprofen intercalated sample was more soluble and more rapidly dissolved than the carbonate intercalated one in acetic/acetate buffer. On the other hand, the dissolution mechanism was invariant with the interlayer anion.

  7. Mechanism of Action of Sulforaphane as a Superoxide Radical Anion and Hydrogen Peroxide Scavenger by Double Hydrogen Transfer: A Model for Iron Superoxide Dismutase.

    PubMed

    Prasad, Ajit Kumar; Mishra, P C

    2015-06-25

    The mechanism of action of sulforaphane as a scavenger of superoxide radical anion (O2(•-)) and hydrogen peroxide (H2O2) was investigated using density functional theory (DFT) in both gas phase and aqueous media. Iron superoxide dismutase (Fe-SOD) involved in scavenging superoxide radical anion from biological media was modeled by a complex consisting of the ferric ion (Fe(3+)) attached to three histidine rings. Reactions related to scavenging of superoxide radical anion by sulforaphane were studied using DFT in the presence and absence of Fe-SOD represented by this model in both gas phase and aqueous media. The scavenging action of sulforaphane toward both superoxide radical anion and hydrogen peroxide was found to involve the unusual mechanism of double hydrogen transfer. It was found that sulforaphane alone, without Fe-SOD, cannot scavenge superoxide radical anion in gas phase or aqueous media efficiently as the corresponding reaction barriers are very high. However, in the presence of Fe-SOD represented by the above-mentioned model, the scavenging reactions become barrierless, and so sulforaphane scavenges superoxide radical anion by converting it to hydrogen peroxide efficiently. Further, sulforaphane was found to scavenge hydrogen peroxide also very efficiently by converting it into water. Thus, the mechanism of action of sulforaphane as an excellent antioxidant has been unravelled. PMID:26020652

  8. Mechanism of Action of Sulforaphane as a Superoxide Radical Anion and Hydrogen Peroxide Scavenger by Double Hydrogen Transfer: A Model for Iron Superoxide Dismutase.

    PubMed

    Prasad, Ajit Kumar; Mishra, P C

    2015-06-25

    The mechanism of action of sulforaphane as a scavenger of superoxide radical anion (O2(•-)) and hydrogen peroxide (H2O2) was investigated using density functional theory (DFT) in both gas phase and aqueous media. Iron superoxide dismutase (Fe-SOD) involved in scavenging superoxide radical anion from biological media was modeled by a complex consisting of the ferric ion (Fe(3+)) attached to three histidine rings. Reactions related to scavenging of superoxide radical anion by sulforaphane were studied using DFT in the presence and absence of Fe-SOD represented by this model in both gas phase and aqueous media. The scavenging action of sulforaphane toward both superoxide radical anion and hydrogen peroxide was found to involve the unusual mechanism of double hydrogen transfer. It was found that sulforaphane alone, without Fe-SOD, cannot scavenge superoxide radical anion in gas phase or aqueous media efficiently as the corresponding reaction barriers are very high. However, in the presence of Fe-SOD represented by the above-mentioned model, the scavenging reactions become barrierless, and so sulforaphane scavenges superoxide radical anion by converting it to hydrogen peroxide efficiently. Further, sulforaphane was found to scavenge hydrogen peroxide also very efficiently by converting it into water. Thus, the mechanism of action of sulforaphane as an excellent antioxidant has been unravelled.

  9. New mechanism of γ-H2AX generation: Surfactant-induced actin disruption causes deoxyribonuclease I translocation to the nucleus and forms DNA double-strand breaks.

    PubMed

    Zhao, Xiaoxu; Yang, Gang; Toyooka, Tatsushi; Ibuki, Yuko

    2015-12-01

    We previously showed that nonionic surfactants, nonylphenol polyethoxylates (NPEOs), induced phosphorylation of histone H2AX, forming γ-H2AX. In this study, we analyzed the mechanism of γ-H2AX generation by an NPEO with 15 ethylene oxide units (NPEO(15)). In MCF-7 breast carcinoma cells, NPEO(15) treatment induced γ-H2AX in a dose-dependent manner. EDTA and ZnCl2, two inhibitors of deoxyribonuclease I (DNase I), inhibited both the γ-H2AX and DNA double-strand breaks induced by NPEO(15). NPEO(15) disrupted filamentous actin and released free DNase I as detected by cell fractionation analysis. Based on immunofluorescence staining of DNase I and monitoring DNase I-GFP localization, DNase I was translocated from the cytosol to the nucleus of cells after treatment with NPEO(15). This translocation did not occur with the common DNA damage inducers ultraviolet B irradiation and hydrogen peroxide. Other surfactants, Tween 20, Triton X-100 and Nonidet P-40, also generated γ-H2AX. These results show that γ-H2AX induction by surfactants including NPEOs, occurs via a new mechanism involving release of free DNase I with actin disruption. This mechanism is distinct from the process of γ-H2AX generation caused by direct chemically induced DNA damage.

  10. New mechanism of γ-H2AX generation: Surfactant-induced actin disruption causes deoxyribonuclease I translocation to the nucleus and forms DNA double-strand breaks.

    PubMed

    Zhao, Xiaoxu; Yang, Gang; Toyooka, Tatsushi; Ibuki, Yuko

    2015-12-01

    We previously showed that nonionic surfactants, nonylphenol polyethoxylates (NPEOs), induced phosphorylation of histone H2AX, forming γ-H2AX. In this study, we analyzed the mechanism of γ-H2AX generation by an NPEO with 15 ethylene oxide units (NPEO(15)). In MCF-7 breast carcinoma cells, NPEO(15) treatment induced γ-H2AX in a dose-dependent manner. EDTA and ZnCl2, two inhibitors of deoxyribonuclease I (DNase I), inhibited both the γ-H2AX and DNA double-strand breaks induced by NPEO(15). NPEO(15) disrupted filamentous actin and released free DNase I as detected by cell fractionation analysis. Based on immunofluorescence staining of DNase I and monitoring DNase I-GFP localization, DNase I was translocated from the cytosol to the nucleus of cells after treatment with NPEO(15). This translocation did not occur with the common DNA damage inducers ultraviolet B irradiation and hydrogen peroxide. Other surfactants, Tween 20, Triton X-100 and Nonidet P-40, also generated γ-H2AX. These results show that γ-H2AX induction by surfactants including NPEOs, occurs via a new mechanism involving release of free DNase I with actin disruption. This mechanism is distinct from the process of γ-H2AX generation caused by direct chemically induced DNA damage. PMID:26653977

  11. Spectrum sharing in cognitive radio networks--an auction-based approach.

    PubMed

    Wang, Xinbing; Li, Zheng; Xu, Pengchao; Xu, Youyun; Gao, Xinbo; Chen, Hsiao-Hwa

    2010-06-01

    Cognitive radio is emerging as a promising technique to improve the utilization of the radio frequency spectrum. In this paper, we consider the problem of spectrum sharing among primary (or "licensed") users (PUs) and secondary (or "unlicensed") users (SUs). We formulate the problem based on bandwidth auction, in which each SU makes a bid for the amount of spectrum and each PU may assign the spectrum among the SUs by itself according to the information from the SUs without degrading its own performance. We show that the auction is a noncooperative game and that Nash equilibrium (NE) can be its solution. We first consider a single-PU network to investigate the existence and uniqueness of the NE and further discuss the fairness among the SUs under given conditions. Then, we present a dynamic updating algorithm in which each SU achieves NE in a distributed manner. The stability condition of the dynamic behavior for this spectrum-sharing scheme is studied. The discussion is generalized to the case in which there are multiple PUs in the network, where the properties of the NE are shown under appropriate conditions. Simulations were used to evaluate the system performance and verify the effectiveness of the proposed algorithm.

  12. Dynamic NMR study of the mechanisms of double, triple, and quadruple proton and deuteron transfer in cyclic hydrogen bonded solids of pyrazole derivatives.

    PubMed

    Klein, Oliver; Aguilar-Parrilla, Francisco; Lopez, Juan Miguel; Jagerovic, Nadine; Elguero, José; Limbach, Hans-Heinrich

    2004-09-22

    Using dynamic solid state (15)N CPMAS NMR spectroscopy (CP = cross polarization, MAS = magic angle spinning), the kinetics of the degenerate intermolecular double and quadruple proton and deuteron transfers in the cyclic dimer of (15)N labeled polycrystalline 3,5-diphenyl-4-bromopyrazole (DPBrP) and in the cyclic tetramer of (15)N labeled polycrystalline 3,5-diphenylpyrazole (DPP) have been studied in a wide temperature range at different deuterium fractions in the mobile proton sites. Rate constants were measured on a millisecond time scale by line shape analysis of the doubly (15)N labeled compounds, and by magnetization transfer experiments on a second timescale of the singly (15)N labeled compounds in order to minimize the effects of proton-driven (15)N spin diffusion. For DPBrP the multiple kinetic HH/HD/DD isotope effects could be directly obtained. By contrast, four rate constants k(1) to k(4) were obtained for DPP at different deuterium fractions. Whereas k(1) corresponds to the rate constant k(HHHH) of the HHHH isotopolog, an appropriate kinetic reaction model was needed for the kinetic assignment of the other rate constants. Using the model described by Limbach, H. H.; Klein, O.; Lopez Del Amo, J. M.; Elguero, J. Z. Phys. Chem. 2004,218, 17, a concerted quadruple proton-transfer mechanism as well as a stepwise consecutive single transfer mechanism could be excluded. By contrast, using the kinetic assignment k(2) approximately k(3) approximately k(HHHD) approximately k(HDHD) and k(3) approximately k(HDDD) approximately k(DDDD), the results could be explained in terms of a two-step process involving a zwitterionic intermediate. In this mechanism, each reaction step involves the concerted transfer of two hydrons, giving rise to primary kinetic HH/HD/DD isotope effects, whereas the nontransferred hydrons only contribute small secondary effects, which are not resolved experimentally. By contrast, the multiple kinetic isotope effects of the double proton

  13. Von Willebrand factor in patients on mechanical circulatory support – a double-edged sword between bleeding and thrombosis

    PubMed Central

    Kaczmarski, Jacek; Pacholewicz, Jerzy; Zakliczynski, Michal; Gasior, Mariusz; Zembala, Marian

    2015-01-01

    Mechanical circulatory support (MCS) is an umbrella term describing the various technologies used in both short- and long-term management of patients with either end-stage chronic heart failure (HF) or acute HF. Most often, MCS has emerged as a bridge to transplantation, but more recently it is also used as a destination therapy. Mechanical circulatory support includes left ventricular assist device (LVAD) or bi-ventricular assist device (Bi-VAD). Currently, 2- to 3-year survival in carefully selected patients is much better than with medical therapy. However, MCS therapy is hampered by sometimes life-threatening complications including bleeding and device thrombosis. Von Willebrand factor (vWF) has two major functions in haemostasis. First, it plays a crucial role in platelet-subendothelium adhesion and platelet-platelet interactions (aggregation). Second, it is the carrier of factor VIII (FVIII) in plasma. Von Willebrand factor prolongs FVIII half-time by protecting it from proteolytic degradation. It delivers FVIII to the site of vascular injury thus enhancing haemostatic process. On one hand, high plasma levels of vWF have been associated with an increased risk of thrombosis. On the other, defects or deficiencies of vWF underlie the inherited von Willebrand disease or acquired von Willebrand syndrome. Here we review the pathophysiology of thrombosis and bleeding associated with vWF. PMID:26702279

  14. A thermo-hydro-mechanical coupled model in local thermal non-equilibrium for fractured HDR reservoir with double porosity

    NASA Astrophysics Data System (ADS)

    Gelet, R.; Loret, B.; Khalili, N.

    2012-07-01

    The constitutive thermo-hydro-mechanical equations of fractured media are embodied in the theory of mixtures applied to three-phase poroelastic media. The solid skeleton contains two distinct cavities filled with the same fluid. Each of the three phases is endowed with its own temperature. The constitutive relations governing the thermomechanical behavior, generalized diffusion and transfer are structured by, and satisfy, the dissipation inequality. The cavities exchange both mass and energy. Mass exchanges are driven by the jump in scaled chemical potential, and energy exchanges by the jump in coldness. The finite element approximation uses the displacement vector, the two fluid pressures and the three temperatures as primary variables. It is used to analyze a generic hot dry rock geothermal reservoir. Three parameters of the model are calibrated from the thermal outputs of Fenton Hill and Rosemanowes HDR reservoirs. The calibrated model is next applied to simulate circulation tests at the Fenton Hill HDR reservoir. The finer thermo-hydro-mechanical response provided by the dual porosity model with respect to a single porosity model is highlighted in a parameter analysis. Emphasis is put on the influence of the fracture spacing, on the effective stress response and on the permeation of the fluid into the porous blocks. The dual porosity model yields a thermally induced effective stress that is less tensile compared with the single porosity response. This effect becomes significant for large fracture spacings. In agreement with field data, fluid loss is observed to be high initially and to decrease with time.

  15. 47 CFR 27.1213 - Designated entity provisions for BRS in Commission auctions commencing prior to January 1, 2004.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., 2004 for BTA service areas are eligible for special incentives in the auction process. See 47 CFR 1... entity will have both de facto and de jure control of the entity. See 47 CFR 1.2110(i). (g) Records... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS...

  16. 47 CFR 27.1213 - Designated entity provisions for BRS in Commission auctions commencing prior to January 1, 2004.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., 2004 for BTA service areas are eligible for special incentives in the auction process. See 47 CFR 1... entity will have both de facto and de jure control of the entity. See 47 CFR 1.2110(i). (g) Records... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS...

  17. 78 FR 50086 - Notice of Competitive Auction for Solar Energy Development on Public Lands in the State of Colorado

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... Bureau of Land Management Notice of Competitive Auction for Solar Energy Development on Public Lands in... applicant to submit a right-of-way (ROW) application and a plan of development for solar energy projects on... solicitations of interest and ROW applications within two designated Solar Energy Zones (SEZ): Los Mogotes...

  18. 40 CFR 97.721 - Recordation of TR SO2 Group 2 allowance allocations and auction results.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Recordation of TR SO2 Group 2... SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.721 Recordation of TR SO2 Group 2 allowance allocations and auction results. (a) By November 7, 2011, the Administrator will record in each TR SO2 Group...

  19. 40 CFR 97.721 - Recordation of TR SO2 Group 2 allowance allocations and auction results.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Recordation of TR SO2 Group 2... SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.721 Recordation of TR SO2 Group 2 allowance allocations and auction results. (a) By November 7, 2011, the Administrator will record in each TR SO2 Group...

  20. 40 CFR 97.621 - Recordation of TR SO2 Group 1 allowance allocations and auction results.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Recordation of TR SO2 Group 1... SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.621 Recordation of TR SO2 Group 1 allowance allocations and auction results. (a) By November 7, 2011, the Administrator will record in each TR SO2 Group...

  1. 40 CFR 97.621 - Recordation of TR SO2 Group 1 allowance allocations and auction results.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Recordation of TR SO2 Group 1... SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.621 Recordation of TR SO2 Group 1 allowance allocations and auction results. (a) By November 7, 2011, the Administrator will record in each TR SO2 Group...

  2. 47 CFR 27.1213 - Designated entity provisions for BRS in Commission auctions commencing prior to January 1, 2004.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES..., 2004 for BTA service areas are eligible for special incentives in the auction process. See 47 CFR 1... entity will have both de facto and de jure control of the entity. See 47 CFR 1.2110(i). (g)...

  3. 47 CFR 27.1213 - Designated entity provisions for BRS in Commission auctions commencing prior to January 1, 2004.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES..., 2004 for BTA service areas are eligible for special incentives in the auction process. See 47 CFR 1... entity will have both de facto and de jure control of the entity. See 47 CFR 1.2110(i). (g)...

  4. 47 CFR 27.1213 - Designated entity provisions for BRS in Commission auctions commencing prior to January 1, 2004.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES..., 2004 for BTA service areas are eligible for special incentives in the auction process. See 47 CFR 1... entity will have both de facto and de jure control of the entity. See 47 CFR 1.2110(i). (g)...

  5. 30 CFR 285.308 - How will MMS conduct an auction for ROW grants and RUE grants?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and RUE grants? 285.308 Section 285.308 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... Renewable Energy Activities Obtaining Row Grants and Rue Grants § 285.308 How will MMS conduct an auction for ROW grants and RUE grants? (a) If MMS determines that there is competitive interest, we will:...

  6. 31 CFR 356.17 - How and when do I pay for securities awarded in an auction?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 2 2014-07-01 2014-07-01 false How and when do I pay for securities awarded in an auction? 356.17 Section 356.17 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE FISCAL SERVICE SALE AND ISSUE OF MARKETABLE BOOK-ENTRY...

  7. 78 FR 56875 - Tribal Mobility Fund Phase I Auction Rescheduled for December 19, 2013; Notice and Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-16

    ... service support through reverse competitive bidding. The USF/ICC Transformation Order, 76 FR 73830, November 29, 2011 and 76 FR 81562, December 28, 2011, established the Mobility Fund as a universal service... program details. On March 29, 2013, the Bureaus released the Auction 902 Comment Public Notice, 78...

  8. Promoting the "water-wire" mechanism of double proton transfer in [2,2'-bipyridyl]-3,3'-diol by porous gold nanoparticles.

    PubMed

    Nag, Tarak Nath; Das, Tarasankar; Mondal, Somen; Maity, Arnab; Purkayastha, Pradipta

    2015-03-01

    The effect of nanopores in porous gold nanoparticles (Au NPs) on excited-state double proton transfer (DPT) in [2,2'-bipyridyl]-3,3'-diol (BP(OH)2) in an aqueous environment is the main focus of the present work. DPT in BP(OH)2 is known to take place through two mechanisms. In a bulk environment, an open solvated molecule facilitates the process and emits at 460 nm whereas, in a confined situation, formation of a "water wire" between the prototropic centers leads to the transfer of protons. It has been shown spectroscopically in the present study that in the nanovessels provided by nanoporous Au NPs, the unconventional mechanism of DPT through the formation of a "water wire" is promoted due to the presence of a limited number of water molecules around the probe. Experiments in the presence of solid pure Au, Ag and Au/Ag NPs were performed to support our proposition. Time-resolved fluorescence spectral changes confirm our findings.

  9. A new method for high-resolution imaging of Ku foci to decipher mechanisms of DNA double-strand break repair

    PubMed Central

    Britton, Sébastien; Coates, Julia

    2013-01-01

    DNA double-strand breaks (DSBs) are the most toxic of all genomic insults, and pathways dealing with their signaling and repair are crucial to prevent cancer and for immune system development. Despite intense investigations, our knowledge of these pathways has been technically limited by our inability to detect the main repair factors at DSBs in cells. In this paper, we present an original method that involves a combination of ribonuclease- and detergent-based preextraction with high-resolution microscopy. This method allows direct visualization of previously hidden repair complexes, including the main DSB sensor Ku, at virtually any type of DSB, including those induced by anticancer agents. We demonstrate its broad range of applications by coupling it to laser microirradiation, super-resolution microscopy, and single-molecule counting to investigate the spatial organization and composition of repair factories. Furthermore, we use our method to monitor DNA repair and identify mechanisms of repair pathway choice, and we show its utility in defining cellular sensitivities and resistance mechanisms to anticancer agents. PMID:23897892

  10. MicroRNAs form triplexes with double stranded DNA at sequence-specific binding sites; a eukaryotic mechanism via which microRNAs could directly alter gene expression

    DOE PAGES

    Paugh, Steven W.; Coss, David R.; Bao, Ju; Laudermilk, Lucas T.; Grace, Christy R.; Ferreira, Antonio M.; Waddell, M. Brett; Ridout, Granger; Naeve, Deanna; Leuze, Michael Rex; et al

    2016-02-04

    MicroRNAs are important regulators of gene expression, acting primarily by binding to sequence-specific locations on already transcribed messenger RNAs (mRNA). Recent studies indicate that microRNAs may also play a role in up-regulating mRNA transcription levels, although a definitive mechanism has not been established. Double-helical DNA is capable of forming triple-helical structures through Hoogsteen and reverse Hoogsteen interactions in the major groove of the duplex, and we show physical evidence that microRNAs form triple-helical structures with duplex DNA, and identify microRNA sequences that favor triplex formation. We developed an algorithm (Trident) to search genome-wide for potential triplex-forming sites and show thatmore » several mammalian and non-mammalian genomes are enriched for strong microRNA triplex binding sites. We show that those genes containing sequences favoring microRNA triplex formation are markedly enriched (3.3 fold, p<2.2 x 10-16) for genes whose expression is positively correlated with expression of microRNAs targeting triplex binding sequences. As a result, this work has thus revealed a new mechanism by which microRNAs can interact with gene promoter regions to modify gene transcription.« less

  11. Double-tilt in situ TEM holder with multiple electrical contacts and its application in MEMS-based mechanical testing of nanomaterials.

    PubMed

    Bernal, Rodrigo A; Ramachandramoorthy, Rajaprakash; Espinosa, Horacio D

    2015-09-01

    MEMS and other lab-on-a-chip systems are emerging as attractive alternatives to carry out experiments in situ the electron microscope. However, several electrical connections are usually required for operating these setups. Such connectivity is challenging inside the limited space of the TEM side-entry holder. Here, we design, implement and demonstrate a double-tilt TEM holder with capabilities for up to 9 electrical connections, operating in a high-resolution TEM. We describe the operating principle of the tilting and connection mechanisms and the physical implementation of the holder. To demonstrate the holder capabilities, we calibrate the tilting action, which has limits of ±15°, and establish the insulation resistance of the electronics to be 36GΩ, appropriate for measurements of currents down to the nano-amp (nA) regime. Furthermore, we demonstrate tensile testing of silver nanowires using a previously developed MEMS device for mechanical testing, using the implemented holder as the platform for electronic operation and sensing. The implemented holder can potentially have broad application to other areas where MEMS or electrically-actuated setups are used to carry out in situ TEM experiments.

  12. MicroRNAs Form Triplexes with Double Stranded DNA at Sequence-Specific Binding Sites; a Eukaryotic Mechanism via which microRNAs Could Directly Alter Gene Expression

    PubMed Central

    Grace, Christy R.; Ferreira, Antonio M.; Waddell, M. Brett; Ridout, Granger; Naeve, Deanna; Leuze, Michael; LoCascio, Philip F.; Panetta, John C.; Wilkinson, Mark R.; Pui, Ching-Hon; Naeve, Clayton W.; Uberbacher, Edward C.; Bonten, Erik J.; Evans, William E.

    2016-01-01

    MicroRNAs are important regulators of gene expression, acting primarily by binding to sequence-specific locations on already transcribed messenger RNAs (mRNA) and typically down-regulating their stability or translation. Recent studies indicate that microRNAs may also play a role in up-regulating mRNA transcription levels, although a definitive mechanism has not been established. Double-helical DNA is capable of forming triple-helical structures through Hoogsteen and reverse Hoogsteen interactions in the major groove of the duplex, and we show physical evidence (i.e., NMR, FRET, SPR) that purine or pyrimidine-rich microRNAs of appropriate length and sequence form triple-helical structures with purine-rich sequences of duplex DNA, and identify microRNA sequences that favor triplex formation. We developed an algorithm (Trident) to search genome-wide for potential triplex-forming sites and show that several mammalian and non-mammalian genomes are enriched for strong microRNA triplex binding sites. We show that those genes containing sequences favoring microRNA triplex formation are markedly enriched (3.3 fold, p<2.2 × 10−16) for genes whose expression is positively correlated with expression of microRNAs targeting triplex binding sequences. This work has thus revealed a new mechanism by which microRNAs could interact with gene promoter regions to modify gene transcription. PMID:26844769

  13. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  14. A randomized, double-blind, placebo-controlled, cross-over study to evaluate analgesic activity of Terminalia chebula in healthy human volunteers using a mechanical pain model

    PubMed Central

    Pokuri, Venkata Kishan; Kumar, Chiranjeevi Uday; Pingali, Usharani

    2016-01-01

    Background and Aims: To evaluate analgesic activity and safety of single oral dose (1000 mg) of Terminalia chebula using a mechanical pain model in healthy human volunteers. Material and Methods: Twelve healthy volunteers were randomized to receive either single oral dose of 2 capsules of T. chebula 500 mg each or identical placebo capsules in a double-blinded manner. Mechanical pain was assessed using Ugo basile analgesy meter (Randall–Selitto test) before and 3 h after administration of test drug. The parameters evaluated were pain threshold force and time; pain tolerance force and time. A washout period of 1-week was given for crossover between active drug and placebo. Results: Terminalia chebula significantly increased the mean percentage change for pain threshold force and time, and pain tolerance force and time compared to placebo (P < 0.001). The mean percentage change for pain threshold force and time (20.8% and 21.0%) was increased more than that of pain tolerance force and time (13.4% and 13.4%). No adverse drug reaction was reported with either of the study medications during the study period. Conclusion: T. chebula significantly increased pain threshold and pain tolerance compared to placebo. Both the study medications were well tolerated. Further multiple dose studies may be needed to establish the analgesic efficacy of the drug in patients suffering from osteoarthritis, rheumatoid arthritis and other painful conditions. PMID:27625480

  15. Beneficial effects of dark chocolate on exercise capacity in sedentary subjects: underlying mechanisms. A double blind, randomized, placebo controlled trial.

    PubMed

    Taub, Pam R; Ramirez-Sanchez, Israel; Patel, Minal; Higginbotham, Erin; Moreno-Ulloa, Aldo; Román-Pintos, Luis Miguel; Phillips, Paul; Perkins, Guy; Ceballos, Guillermo; Villarreal, Francisco

    2016-09-14

    In heart failure patients the consumption of (-)-epicatechin ((-)-Epi)-rich cocoa can restore skeletal muscle (SkM) mitochondrial structure and decrease biomarkers of oxidative stress. However, nothing is known about its effects on exercise capacity and underlying mechanisms in normal, sedentary subjects. Twenty normal, sedentary subjects (∼50 years old) were randomized to placebo or dark chocolate (DC) groups and consumed 20 g of the products for 3 months. Subjects underwent before and after treatment, bicycle ergometry to assess VO2 max and work, SkM biopsy to assess changes in mitochondrial density, function and oxidative stress and blood sampling to assess metabolic endpoints. Seventeen subjects completed the trial. In the DC group (n = 9), VO2 max increased (17% increase, p = 0.056) as well as maximum work (watts) achieved (p = 0.026) with no changes with placebo (n = 8). The DC group evidenced increases in HDL levels (p = 0.005) and decreased triglycerides (p = 0.07). With DC, SkM evidenced significant increases in protein levels for LKB1, AMPK and PGC1α and in their active forms (phosphorylated AMPK and LKB1) as well as in citrate synthase activity while no changes were observed in mitochondrial density. With DC, significant increases in SkM reduced glutathione levels and decreases in protein carbonylation were observed. Improvements in maximum work achieved and VO2 max may be due to DC activation of upstream control systems and enhancement of SkM mitochondria efficiency. Larger clinical studies are warranted to confirm these observations. PMID:27491778

  16. Identifying Oneself with the Face of Someone Else Impairs the Egocentered Visuo-spatial Mechanisms: A New Double Mirror Paradigm to Study Self-other Distinction and Interaction.

    PubMed

    Thirioux, Bérangère; Wehrmann, Moritz; Langbour, Nicolas; Jaafari, Nematollah; Berthoz, Alain

    2016-01-01

    Looking at our face in a mirror is one of the strongest phenomenological experiences of the Self in which we need to identify the face as reflected in the mirror as belonging to us. Recent behavioral and neuroimaging studies reported that self-face identification not only relies upon visual-mnemonic representation of one's own face but also upon continuous updating and integration of visuo-tactile signals. Therefore, bodily self-consciousness plays a major role in self-face identification, with respect to interplay between unisensory and multisensory processing. However, if previous studies demonstrated that the integration of multisensory body-related signals contributes to the visual processing of one's own face, there is so far no data regarding how self-face identification, inversely, contributes to bodily self-consciousness. In the present study, we tested whether self-other face identification impacts either the egocentered or heterocentered visuo-spatial mechanisms that are core processes of bodily self-consciousness and sustain self-other distinction. For that, we developed a new paradigm, named "Double Mirror." This paradigm, consisting of a semi-transparent double mirror and computer-controlled Light Emitting Diodes, elicits self-other face merging illusory effect in ecologically more valid conditions, i.e., when participants are physically facing each other and interacting. Self-face identification was manipulated by exposing pairs of participants to an Interpersonal Visual Stimulation in which the reflection of their faces merged in the mirror. Participants simultaneously performed visuo-spatial and mental own-body transformation tasks centered on their own face (egocentered) or the face of their partner (heterocentered) in the pre- and post-stimulation phase. We show that self-other face identification altered the egocentered visuo-spatial mechanisms. Heterocentered coding was preserved. Our data suggest that changes in self-face identification induced

  17. Identifying Oneself with the Face of Someone Else Impairs the Egocentered Visuo-spatial Mechanisms: A New Double Mirror Paradigm to Study Self–other Distinction and Interaction

    PubMed Central

    Thirioux, Bérangère; Wehrmann, Moritz; Langbour, Nicolas; Jaafari, Nematollah; Berthoz, Alain

    2016-01-01

    Looking at our face in a mirror is one of the strongest phenomenological experiences of the Self in which we need to identify the face as reflected in the mirror as belonging to us. Recent behavioral and neuroimaging studies reported that self-face identification not only relies upon visual-mnemonic representation of one’s own face but also upon continuous updating and integration of visuo-tactile signals. Therefore, bodily self-consciousness plays a major role in self-face identification, with respect to interplay between unisensory and multisensory processing. However, if previous studies demonstrated that the integration of multisensory body-related signals contributes to the visual processing of one’s own face, there is so far no data regarding how self-face identification, inversely, contributes to bodily self-consciousness. In the present study, we tested whether self–other face identification impacts either the egocentered or heterocentered visuo-spatial mechanisms that are core processes of bodily self-consciousness and sustain self–other distinction. For that, we developed a new paradigm, named “Double Mirror.” This paradigm, consisting of a semi-transparent double mirror and computer-controlled Light Emitting Diodes, elicits self–other face merging illusory effect in ecologically more valid conditions, i.e., when participants are physically facing each other and interacting. Self-face identification was manipulated by exposing pairs of participants to an Interpersonal Visual Stimulation in which the reflection of their faces merged in the mirror. Participants simultaneously performed visuo-spatial and mental own-body transformation tasks centered on their own face (egocentered) or the face of their partner (heterocentered) in the pre- and post-stimulation phase. We show that self–other face identification altered the egocentered visuo-spatial mechanisms. Heterocentered coding was preserved. Our data suggest that changes in self

  18. Identifying Oneself with the Face of Someone Else Impairs the Egocentered Visuo-spatial Mechanisms: A New Double Mirror Paradigm to Study Self–other Distinction and Interaction

    PubMed Central

    Thirioux, Bérangère; Wehrmann, Moritz; Langbour, Nicolas; Jaafari, Nematollah; Berthoz, Alain

    2016-01-01

    Looking at our face in a mirror is one of the strongest phenomenological experiences of the Self in which we need to identify the face as reflected in the mirror as belonging to us. Recent behavioral and neuroimaging studies reported that self-face identification not only relies upon visual-mnemonic representation of one’s own face but also upon continuous updating and integration of visuo-tactile signals. Therefore, bodily self-consciousness plays a major role in self-face identification, with respect to interplay between unisensory and multisensory processing. However, if previous studies demonstrated that the integration of multisensory body-related signals contributes to the visual processing of one’s own face, there is so far no data regarding how self-face identification, inversely, contributes to bodily self-consciousness. In the present study, we tested whether self–other face identification impacts either the egocentered or heterocentered visuo-spatial mechanisms that are core processes of bodily self-consciousness and sustain self–other distinction. For that, we developed a new paradigm, named “Double Mirror.” This paradigm, consisting of a semi-transparent double mirror and computer-controlled Light Emitting Diodes, elicits self–other face merging illusory effect in ecologically more valid conditions, i.e., when participants are physically facing each other and interacting. Self-face identification was manipulated by exposing pairs of participants to an Interpersonal Visual Stimulation in which the reflection of their faces merged in the mirror. Participants simultaneously performed visuo-spatial and mental own-body transformation tasks centered on their own face (egocentered) or the face of their partner (heterocentered) in the pre- and post-stimulation phase. We show that self–other face identification altered the egocentered visuo-spatial mechanisms. Heterocentered coding was preserved. Our data suggest that changes in self

  19. Human remains sold to the highest bidder! A snapshot of the buying and selling of human skeletal remains on eBay, an Internet auction site.

    PubMed

    Huxley, Angie K; Finnegan, Michael

    2004-01-01

    Internet auction sites have become increasingly popular, with diverse items up for sale to the public worldwide. The purposes of this paper are to inform the forensic community that human skeletal remains, old and new, are for sale on the eBay internet auction site, and to advise forensic scientists that eBay does not use a forensic anthropologist to assess photographs of these materials. Over the last few years, this website was "surfed," with numerous auctions during this period. After contacting eBay by email, representatives responded that they adhere to Native American Grave Protection and Repatriation Act (NAGPRA) and that their website indicates that auctions must state that sale of human remains is for instructional purposes only. Based on the photographs, the remains appear to be of prehistoric and modern origin. An unfortunate consequence of such sale may generate interest in stealing remains from graves, mortuaries, hospitals, or county morgues worldwide. PMID:14979339

  20. 31 CFR 356.4 - What are the book-entry systems in which auctioned Treasury securities may be issued or maintained?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Treasury securities in an auction, securities awarded as a result of those bids are generally held in the... government and international agencies and foreign central banks. In their accounts, depository...

  1. 31 CFR 356.4 - What are the book-entry systems in which auctioned Treasury securities may be issued or maintained?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Treasury securities in an auction, securities awarded as a result of those bids are generally held in the... government and international agencies and foreign central banks. In their accounts, depository...

  2. 31 CFR 356.4 - What are the book-entry systems in which auctioned Treasury securities may be issued or maintained?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Treasury securities in an auction, securities awarded as a result of those bids are generally held in the... government and international agencies and foreign central banks. In their accounts, depository...

  3. Effects of information on young consumers' willingness to pay for genetically modified food: experimental auction analysis.

    PubMed

    Kajale, Dilip B; Becker, T C

    2014-01-01

    This study examines the effects of information on consumers' willingness to pay (WTP) for genetically modified food (GMF). We used Vickrey second price experimental auction method for elicitation of consumer WTP for GM potato chips and GM soya-chocolate bar. The sample used in this study was university students from Delhi, India. Four information formats (positive, negative, no information, and combined information about GM technology) were used for the examination. The results show that, when students received the combine information they were willing to pay around 17%-20% premium for GMF and when received the negative information they demanded around 22% discount for GMF. While the positive- and the no-information formats alone have no considerable effect on consumers' WTP for GMF. Overall, our findings suggest that while doing marketing of GMF in India, the best strategy is to provide combined information about GM technology.

  4. Joint bidding, information pooling, and the performance of petroleum lease auctions

    SciTech Connect

    DeBrock, L.M.; Smith, J.L.

    1983-01-01

    This article uses a game-theoretic bidding model to examine the effect of joint bidding in offshore petroleum lease auctions. It shows that joint bidding increases the total social value of the lease offering and, in most cases, does not significantly decrease the percentage of social value captured by the government. These results follow from the fact that pooling of information concerning a prior unknown tract values allows for more accurate estimates. The anticompetitive effect of a reduced number of bidders tends to be offset by the well-known fact that better informed participants bid more aggressively. The findings are striking in that the model abstracts entirely from the effects of increased entry and greater risk diversification, the two common arguments in support of joint bidding. 12 references, 13 footnotes, 3 figures, 2 tables.

  5. Effects of information on young consumers' willingness to pay for genetically modified food: experimental auction analysis.

    PubMed

    Kajale, Dilip B; Becker, T C

    2014-01-01

    This study examines the effects of information on consumers' willingness to pay (WTP) for genetically modified food (GMF). We used Vickrey second price experimental auction method for elicitation of consumer WTP for GM potato chips and GM soya-chocolate bar. The sample used in this study was university students from Delhi, India. Four information formats (positive, negative, no information, and combined information about GM technology) were used for the examination. The results show that, when students received the combine information they were willing to pay around 17%-20% premium for GMF and when received the negative information they demanded around 22% discount for GMF. While the positive- and the no-information formats alone have no considerable effect on consumers' WTP for GMF. Overall, our findings suggest that while doing marketing of GMF in India, the best strategy is to provide combined information about GM technology. PMID:24735210

  6. Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

    NASA Astrophysics Data System (ADS)

    Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua; Wang, Qingguo; Xu, Jing

    2016-11-01

    Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in the temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180-914 cm-1) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention.

  7. Non-double-couple mechanism of moderate earthquakes occurred in Lower Siang region of Arunachal Himalaya: Evidence of factors affecting non-DC

    NASA Astrophysics Data System (ADS)

    Kumar, Rohtash; Gupta, S. C.; Kumar, Arjun

    2015-02-01

    Moment Tensor solutions of 104 earthquakes which were observed at local distances in Lower Siang region of Arunachal Himalaya have been estimated using ISOLA code. The magnitude range of analyzed earthquakes lies between 1.8 (Mw) and 5.3 (Mw). Out of 104 earthquakes, only 32 events are having good data. The signal noise ratio of these 32 events is greater than 6 with magnitude greater than 2.5. All possible sources of non-DC such as, noise present in the data, depth of the source, low azimuthal coverage of the event and non-DC as a part of real earthquake source process are examined. The study reveals that non-DC is highly dependent on the source depth as comparatively shallow events shows high CLVD%. The CLVD is also highly affected by the noise present in the data. Another factor is the magnitude of the event. The high magnitude event shows quite high DC%. So the source mechanisms of high magnitude events are double couple (DC).

  8. Truthful Incentive Mechanisms for Social Cost Minimization in Mobile Crowdsourcing Systems

    PubMed Central

    Duan, Zhuojun; Yan, Mingyuan; Cai, Zhipeng; Wang, Xiaoming; Han, Meng; Li, Yingshu

    2016-01-01

    With the emergence of new technologies, mobile devices are capable of undertaking computational and sensing tasks. A large number of users with these mobile devices promote the formation of the Mobile Crowdsourcing Systems (MCSs). Within a MCS, each mobile device can contribute to the crowdsourcing platform and get rewards from it. In order to achieve better performance, it is important to design a mechanism that can attract enough participants with mobile devices and then allocate the tasks among participants efficiently. In this paper, we are interested in the investigation of tasks allocation and price determination in MCSs. Two truthful auction mechanisms are proposed for different working patterns. A Vickrey–Clarke–Groves (VCG)-based auction mechanism is proposed to the continuous working pattern, and a suboptimal auction mechanism is introduced for the discontinuous working pattern. Further analysis shows that the proposed mechanisms have the properties of individual rationality and computational efficiencies. Experimental results suggest that both mechanisms guarantee all the mobile users bidding with their truthful values and the optimal maximal social cost can be achieved in the VCG-based auction mechanism. PMID:27058541

  9. Truthful Incentive Mechanisms for Social Cost Minimization in Mobile Crowdsourcing Systems.

    PubMed

    Duan, Zhuojun; Yan, Mingyuan; Cai, Zhipeng; Wang, Xiaoming; Han, Meng; Li, Yingshu

    2016-01-01

    With the emergence of new technologies, mobile devices are capable of undertaking computational and sensing tasks. A large number of users with these mobile devices promote the formation of the Mobile Crowdsourcing Systems (MCSs). Within a MCS, each mobile device can contribute to the crowdsourcing platform and get rewards from it. In order to achieve better performance, it is important to design a mechanism that can attract enough participants with mobile devices and then allocate the tasks among participants efficiently. In this paper, we are interested in the investigation of tasks allocation and price determination in MCSs. Two truthful auction mechanisms are proposed for different working patterns. A Vickrey-Clarke-Groves (VCG)-based auction mechanism is proposed to the continuous working pattern, and a suboptimal auction mechanism is introduced for the discontinuous working pattern. Further analysis shows that the proposed mechanisms have the properties of individual rationality and computational efficiencies. Experimental results suggest that both mechanisms guarantee all the mobile users bidding with their truthful values and the optimal maximal social cost can be achieved in the VCG-based auction mechanism. PMID:27058541

  10. Essays on empirical analysis of multi-unit auctions: Impacts of financial transmission rights on the restructured electricity industry

    NASA Astrophysics Data System (ADS)

    Zang, Hailing

    This dissertation uses recently developed empirical methodologies for the study of multi-unit auctions to test the impacts of Financial Transmission Rights (FTRs) on the competitiveness of restructured electricity markets. FTRs are a special type of financial option that hedge against volatility in the cost of transporting electricity over the grid. Policy makers seek to use the prices of FTRs as market signals to incentivize efficient investment and utilization of transmission capacity. However, prices will not send the correct signals if market participants strategically use FTRs. This dissertation uses data from the Texas electricity market to test whether the prices of FTRs are efficient to achieve such goals. The auctions studied are multi-unit, uniform-price, sealed-bid auctions. The first part of the dissertation studies the auctions on the spot market of the wholesale electricity industry. I derive structural empirical models to test theoretical predictions as to whether bidders fully internalize the effect of FTRs on profits into their bidding decisions. I find that bidders are learning as to how to optimally bid above marginal cost for their inframarginal capacities. The bidders also learn to bid to include FTRs into their profit maximization problem during the course of the first year. But starting from the second year, they deviated from optimal bidding that includes FTRs in the profit maximization problems. Counterfactual analysis show that the primary effect of FTRs on market outcomes is changing the level of prices rather than production efficiency. Finally, I find that in most months, the current allocations of FTRs are statistically equivalent to the optimal allocations. The second part of the dissertation studies the bidding behavior in the FTR auctions. I find that FTRs' strategic impact on the FTR purchasing behavior is significant for large bidders---firms exercising market power in the FTR auctions. Second, trader forecasts future FTR credit

  11. Non-double-couple mechanisms of microearthquakes induced during the 2000 injection experiment at the KTB site, Germany: A result of tensile faulting or anisotropy of a rock?

    NASA Astrophysics Data System (ADS)

    Vavryčuk, Václav; Bohnhoff, Marco; Jechumtálová, Zuzana; Kolář, Petr; Šílený, Jan

    2008-08-01

    Moment tensors of microearthquakes induced during the 2000 injection experiment at the KTB deep drilling borehole at a depth level of 5.4 km are studied. A family of 37 most reliable moment tensors contains significant non-double-couple (non-DC) components. The DC is on average 60% and the non-DC is 40%. Fault plane solutions computed from the DC part show preferred strike-slip mechanisms with small normal or reverse components. A predominant azimuth of P and T axes is in the range of N320°-340°E and of N230°-250°E, respectively. The non-DC components contain both the isotropic (ISO) and compensated linear vector dipole (CLVD) components. The mean value of ISO is 1.5%, the mean value of CLVD is - 5.7%. The predominantly negative CLVD components are inconsistent with the concept of the non-DC mechanisms as a result of tensile faulting due to fluid injection into the rock. The main origin of the non-DC components is probably anisotropy in the focal area. The other origins are errors produced by mismodelling of the medium when calculating the Green functions, and numerical errors produced by noise and limitations of input data. Adopting four alternative models of anisotropy obtained by other seismic measurements at the KTB, we have employed the non-DC components for estimating an optimum orientation of anisotropy in the focal area. The optimum orientation of the symmetry plane of anisotropy is nearly vertical with a strike of N335°-340°E. This strike coincides well with the strike of 330° typical for many major lithological units and faults and with the orientation of the transversely isotropic model inferred by other authors. After removing the anisotropy effects from the moment tensors by calculating the source tensors, the distribution of ISO is significantly narrowed. This indicates predominantly shear, but not tensile faulting.

  12. Curcumin and major depression: a randomised, double-blind, placebo-controlled trial investigating the potential of peripheral biomarkers to predict treatment response and antidepressant mechanisms of change.

    PubMed

    Lopresti, Adrian L; Maes, Michael; Meddens, Marc J M; Maker, Garth L; Arnoldussen, Eddy; Drummond, Peter D

    2015-01-01

    A recent randomised, double-blind, placebo controlled study conducted by our research group, provided partial support for the efficacy of supplementation with a patented curcumin extract (500 mg, twice daily) for 8 weeks in reducing depressive symptoms in people with major depressive disorder. In the present paper, a secondary, exploratory analysis of salivary, urinary and blood biomarkers collected during this study was conducted to identify potential antidepressant mechanisms of action of curcumin. Pre and post-intervention samples were provided by 50 participants diagnosed with major depressive disorder, and the Inventory of Depressive Symptomatology self-rated version (IDS-SR30) was used as the primary depression outcome measure. Compared to placebo, 8 weeks of curcumin supplementation was associated with elevations in urinary thromboxane B2 (p<0.05), and substance P (p<0.001); while placebo supplementation was associated with reductions in aldosterone (p<0.05) and cortisol (p<0.05). Higher baseline plasma endothelin-1 (rs=-0.587; p<0.01) and leptin (rs=-0.470; p<0.05) in curcumin-treated individuals was associated with greater reductions in IDS-SR30 score after 8 weeks of treatment. Our findings demonstrate that curcumin supplementation influences several biomarkers that may be associated with its antidepressant mechanisms of action. Plasma concentrations of leptin and endothelin-1 seem to have particular relevance to treatment outcome. Further investigations using larger samples sizes are required to elucidate these findings, as the multiple statistical comparisons completed in this study increased the risk of type I errors.

  13. A Good Beginning Makes a Good Market: The Effect of Different Market Opening Structures on Market Quality

    PubMed Central

    Hinterleitner, Gernot; Leopold-Wildburger, Ulrike; Mestel, Roland; Palan, Stefan

    2015-01-01

    This paper deals with the market structure at the opening of the trading day and its influence on subsequent trading. We compare a single continuous double auction and two complement markets with different call auction designs as opening mechanisms in a unified experimental framework. The call auctions differ with respect to their levels of transparency. We find that a call auction not only improves market efficiency and liquidity at the beginning of the trading day when compared to the stand-alone continuous double auction, but also causes positive spillover effects on subsequent trading. Concerning the design of the opening call auction, we find no significant differences between the transparent and nontransparent specification with respect to opening prices and liquidity. In the course of subsequent continuous trading, however, market quality is slightly higher after a nontransparent call auction. PMID:26351653

  14. Double-Entry Bookkeeping.

    ERIC Educational Resources Information Center

    Snyder, Herbert

    1999-01-01

    Explains the principles and mechanics of double-entry bookkeeping as a part of the accounting cycle to produce a functioning set of accounting records. Suggests that libraries need to have accurate and timely information about their spending to gain financial control and protect against fraud and abuse. (LRW)

  15. Right of way in the sky: two problems in aircraft self-separation and the auction-based solution.

    PubMed

    Erev, Ido; Barron, Greg; Remington, Roger

    2004-01-01

    There has been a growing movement to give commercial airliners more freedom in choosing their routes and responsibility for detecting and avoiding conflicts. These "free flight" concepts must contain new rules for assigning right of way in potential conflict situations. To evaluate the effect of prospective rules, the current paper derives the expected response of agents who exhibit different levels of sophistication. Traditional game theoretic analysis is used to derive the behavior of rational agents. Computer simulations are used to predict the behavior of boundedly rational reinforcement learners. The results reveal that several seemingly reasonable, straightforward right-of-way rules might lead to undesirable outcomes. These problematic results are robust to the assumed level of rationality. It is shown that these problems can be alleviated by using auctions to resolve competition for right of way. Actual or potential applications of this research include the usage of second price auctions to address right-of-way and similar conflicts.

  16. Microscopic mechanism underlying double-state lasing in an InAs/GaAs quantum dot laser diode elucidated using coupled rate equations and the spontaneous emission recorded from a window structure.

    PubMed

    Lee, J M; Jeon, B H; Kim, J; Lee, D

    2015-12-14

    We investigated the microscopic mechanism underlying the double-state lasing behavior (simultaneous lasing at the ground state [GS] and excited state [ES]) in InAs/GaAs quantum dot (QD) laser diodes. The ES and GS lasing processes that contributed to double-state lasing were examined experimentally and theoretically. Experiments were conducted in which spontaneous emission from a window of a QD laser diode was examined under lasing conditions, and numerical simulations were performed using a coupled rate equation model of the QD microstates. The findings showed that, when carrier relaxation from the ES to the GS was sufficiently slow, double-state lasing occurred. Additionally, ES lasing was found to arise not from the QD group undergoing GS lasing, but rather from another QD group in which the states were lower in energy and outside of the homogeneous bandwidth.

  17. Analysis of Repair Mechanisms following an Induced Double-Strand Break Uncovers Recessive Deleterious Alleles in the Candida albicans Diploid Genome

    PubMed Central

    Feri, Adeline; Loll-Krippleber, Raphaël; Commere, Pierre-Henri; Maufrais, Corinne; Sertour, Natacha; Schwartz, Katja; Sherlock, Gavin; Bougnoux, Marie-Elisabeth

    2016-01-01

    ABSTRACT The diploid genome of the yeast Candida albicans is highly plastic, exhibiting frequent loss-of-heterozygosity (LOH) events. To provide a deeper understanding of the mechanisms leading to LOH, we investigated the repair of a unique DNA double-strand break (DSB) in the laboratory C. albicans SC5314 strain using the I-SceI meganuclease. Upon I-SceI induction, we detected a strong increase in the frequency of LOH events at an I-SceI target locus positioned on chromosome 4 (Chr4), including events spreading from this locus to the proximal telomere. Characterization of the repair events by single nucleotide polymorphism (SNP) typing and whole-genome sequencing revealed a predominance of gene conversions, but we also observed mitotic crossover or break-induced replication events, as well as combinations of independent events. Importantly, progeny that had undergone homozygosis of part or all of Chr4 haplotype B (Chr4B) were inviable. Mining of genome sequencing data for 155 C. albicans isolates allowed the identification of a recessive lethal allele in the GPI16 gene on Chr4B unique to C. albicans strain SC5314 which is responsible for this inviability. Additional recessive lethal or deleterious alleles were identified in the genomes of strain SC5314 and two clinical isolates. Our results demonstrate that recessive lethal alleles in the genomes of C. albicans isolates prevent the occurrence of specific extended LOH events. While these and other recessive lethal and deleterious alleles are likely to accumulate in C. albicans due to clonal reproduction, their occurrence may in turn promote the maintenance of corresponding nondeleterious alleles and, consequently, heterozygosity in the C. albicans species. PMID:27729506

  18. Double Layers in Astrophysics

    NASA Technical Reports Server (NTRS)

    Williams, Alton C. (Editor); Moorehead, Tauna W. (Editor)

    1987-01-01

    Topics addressed include: laboratory double layers; ion-acoustic double layers; pumping potential wells; ion phase-space vortices; weak double layers; electric fields and double layers in plasmas; auroral double layers; double layer formation in a plasma; beamed emission from gamma-ray burst source; double layers and extragalactic jets; and electric potential between plasma sheet clouds.

  19. Characterizing the Mechanism of Action of Double-Stranded RNA Activity against Western Corn Rootworm (Diabrotica virgifera virgifera LeConte)

    PubMed Central

    Bolognesi, Renata; Ramaseshadri, Parthasarathy; Anderson, Jerry; Bachman, Pamela; Clinton, William; Flannagan, Ronald; Ilagan, Oliver; Lawrence, Christina; Levine, Steven; Moar, William; Mueller, Geoffrey; Tan, Jianguo; Uffman, Joshua; Wiggins, Elizabeth; Heck, Gregory; Segers, Gerrit

    2012-01-01

    RNA interference (RNAi) has previously been shown to be effective in western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) larvae via oral delivery of synthetic double-stranded RNA (dsRNA) in an artificial diet bioassay, as well as by ingestion of transgenic corn plant tissues engineered to express dsRNA. Although the RNAi machinery components appear to be conserved in Coleopteran insects, the key steps in this process have not been reported for WCR. Here we characterized the sequence of events that result in mortality after ingestion of a dsRNA designed against WCR larvae. We selected the Snf7 ortholog (DvSnf7) as the target mRNA, which encodes an essential protein involved in intracellular trafficking. Our results showed that dsRNAs greater than or equal to approximately 60 base-pairs (bp) are required for biological activity in artificial diet bioassays. Additionally, 240 bp dsRNAs containing a single 21 bp match to the target sequence were also efficacious, whereas 21 bp short interfering (si) RNAs matching the target sequence were not. This result was further investigated in WCR midgut tissues: uptake of 240 bp dsRNA was evident in WCR midgut cells while a 21 bp siRNA was not, supporting the size-activity relationship established in diet bioassays. DvSnf7 suppression was observed in a time-dependent manner with suppression at the mRNA level preceding suppression at the protein level when a 240 bp dsRNA was fed to WCR larvae. DvSnf7 suppression was shown to spread to tissues beyond the midgut within 24 h after dsRNA ingestion. These events (dsRNA uptake, target mRNA and protein suppression, systemic spreading, growth inhibition and eventual mortality) comprise the overall mechanism of action by which DvSnf7 dsRNA affects WCR via oral delivery and provides insights as to how targeted dsRNAs in general are active against insects. PMID:23071820

  20. A controlled auction market is a practical solution to the shortage of transplantable organs.

    PubMed

    Kevorkian, J

    1992-01-01

    All attempts relying on pure altruism to meet the demand for transplantable donor organs have failed and continue to fail. The incentive of commercialization of an organ market would seem to be the only practical solution at this time. It is almost impossible to set fixed prices for such priceless items as human organs. The only fair, honest, and feasible approach is the establishment of a free and voluntary national or international auction system under the strict supervision and control of an exclusive, specially created administrative entity free of governmental or other partisan interference. The resultant flow of funds could be enormous and would enhance the welfare of all strata of society. Wealthy buyers would be removed from current waiting lists; the donor pool greatly expanded to perhaps surplus; the resultant money used to relieve the financial burdens on families involved, hospitals, insurance companies--and also used to buy organs for the indigent on waiting lists, pay for surgeries and hospitalization, and thereby increase the income and surgical experience of more surgeons. This proposed new system should include all live as well as brain-dead donors, cadavers and consenting individuals facing purposeful and pointless destruction by judicial execution.

  1. Game auction prices are not related to biodiversity contributions of southern African ungulates and large carnivores.

    PubMed

    Dalerum, Fredrik; Miranda, Maria

    2016-01-01

    There is an urgent need for human societies to become environmentally sustainable. Because public policy is largely driven by economic processes, quantifications of the relationship between market prices and environmental values can provide important information for developing strategies towards sustainability. Wildlife in southern Africa is often privately owned and traded at game auctions to be utilized for commercial purposes mostly related to tourism. This market offers an interesting opportunity to evaluate how market prices relate to biologically meaningful species characteristics. In this market, prices were not correlated with species contributions to either phylogenetic or functional diversity, and species contributions to phylogenetic or functional diversity did not influence the trends in prices over time for the past 20 years. Since this economic market did not seem to appreciate evolutionary or ecologically relevant characteristics, we question if the game tourism market may contribute towards biodiversity conservation in southern Africa. We suggest that market prices in general may have limited values as guides for directing conservation and environmental management. We further suggest that there is a need to evaluate what humans value in biological organisms, and how potentially necessary shifts in such values can be instigated. PMID:26911226

  2. Estimating the impact of different cigarette package warning label policies: the auction method.

    PubMed

    Thrasher, James F; Rousu, Matthew C; Anaya-Ocampo, Rafael; Reynales-Shigematsu, Luz Myriam; Arillo-Santillán, Edna; Hernández-Avila, Mauricio

    2007-12-01

    The study estimated the reduction in demand associated with implementing cigarette package warning labels that contain imagery illustrating the consequences of smoking. The experimental auction method was used, wherein adult smokers in Mexico (n=89) placed separate bids on two packs of cigarettes: one with a text-only warning label and the other with a warning label that included text and a graphic image. Differences in the values attributed to each pack were assessed using t-tests and multivariate regression. The pack with the graphic image had a mean attributed value which was 17% lower ($3.21 pesos) than the pack with the text-only warning, and this difference remained statistically significant within subgroups defined by sociodemographics, amount of smoking, number of quit attempts, and levels of perceived smoking risks. In the multivariate model, the difference in attributed values was greater among females than males, but no such differences were found for other sociodemographic or smoking-related variables. The consistently lower value that smokers attributed to cigarette packages with the graphic warning label indicates that these labels are likely to reduce cigarette demand. PMID:17630221

  3. Reverse Auction: A Potential Strategy for Reduction of Pharmacological Therapy Cost

    PubMed Central

    Brandão, Sara Michelly Gonçalves; Issa, Victor Sarli; Ayub-Ferreira, Silvia Moreira; Storer, Samantha; Gonçalves, Bianca Gigliotti; Santos, Valter Garcia; Carvas Junior, Nelson; Guimarães, Guilherme Veiga; Bocchi, Edimar Alcides

    2015-01-01

    Background Polypharmacy is a significant economic burden. Objective We tested whether using reverse auction (RA) as compared with commercial pharmacy (CP) to purchase medicine results in lower pharmaceutical costs for heart failure (HF) and heart transplantation (HT) outpatients. Methods We compared the costs via RA versus CP in 808 HF and 147 HT patients followed from 2009 through 2011, and evaluated the influence of clinical and demographic variables on cost. Results The monthly cost per patient for HF drugs acquired via RA was $10.15 (IQ 3.51-40.22) versus $161.76 (IQ 86.05‑340.15) via CP; for HT, those costs were $393.08 (IQ 124.74-774.76) and $1,207.70 (IQ 604.48-2,499.97), respectively. Conclusion RA may reduce the cost of prescription drugs for HF and HT, potentially making HF treatment more accessible. Clinical characteristics can influence the cost and benefits of RA. RA may be a new health policy strategy to reduce costs of prescribed medications for HF and HT patients, reducing the economic burden of treatment. PMID:26200898

  4. Game auction prices are not related to biodiversity contributions of southern African ungulates and large carnivores

    PubMed Central

    Dalerum, Fredrik; Miranda, Maria

    2016-01-01

    There is an urgent need for human societies to become environmentally sustainable. Because public policy is largely driven by economic processes, quantifications of the relationship between market prices and environmental values can provide important information for developing strategies towards sustainability. Wildlife in southern Africa is often privately owned and traded at game auctions to be utilized for commercial purposes mostly related to tourism. This market offers an interesting opportunity to evaluate how market prices relate to biologically meaningful species characteristics. In this market, prices were not correlated with species contributions to either phylogenetic or functional diversity, and species contributions to phylogenetic or functional diversity did not influence the trends in prices over time for the past 20 years. Since this economic market did not seem to appreciate evolutionary or ecologically relevant characteristics, we question if the game tourism market may contribute towards biodiversity conservation in southern Africa. We suggest that market prices in general may have limited values as guides for directing conservation and environmental management. We further suggest that there is a need to evaluate what humans value in biological organisms, and how potentially necessary shifts in such values can be instigated. PMID:26911226

  5. Double shell liner implosions

    SciTech Connect

    Sorokin, S. A.; Chaikovsky, S. A.

    1997-05-05

    Experiments on the double shell liner (DSL) implosions with and without an initial axial magnetic were performed on the SNOP-3 pulse generator (1.1 MA, 100 ns). In implosions of a DSL without an initial axial magnetic field, high radial compressions of the inner shell were observed, as in previous experiments with an initial axial magnetic field. Possible mechanisms for the formation of the initial azimuthal magnetic field are discussed.

  6. Double aortic arch

    MedlinePlus

    Aortic arch anomaly; Double arch; Congenital heart defect - double aortic arch; Birth defect heart - double aortic arch ... aorta is a single arch that leaves the heart and moves leftward. In double aortic arch, some ...

  7. Factors affecting the selling price of feeder cattle sold at Arkansas livestock auctions in 2005.

    PubMed

    Barham, B L; Troxel, T R

    2007-12-01

    Data were collected from 15 Arkansas livestock auctions to determine factors affecting selling price. Data included how calves were sold (single or groups), sex, breed or breed type, color, muscle thickness, horn status, frame score, fill, body condition, age, health, BW, and price. Data were randomly collected on 52,401 lots consisting of 105,542 calves. Selling prices for steers ($124.20 +/- 0.07), bulls ($117.93 +/- 0.12), and heifers ($112.81 +/- 0.07) were different from each other (P <0.001). Hereford x Charolais feeder calves sold for the highest price ($122.66 +/- 0.14) and Longhorns sold for the lowest price ($74.52 +/- 0.46). Yellow feeder cattle received the highest selling price ($96.47 +/- 0.12), and spotted or striped feeder cattle received the lowest price ($83.84 +/- 0.23). The selling price of singles was lower than the price for calves sold in groups of 6 or more ($117.26 +/- 0.06 vs. $122.61 +/- 0.21; P <0.001). For cattle classified as having muscle scores of 1, 2, 3, and 4, selling prices were $120.45 +/- 0.05, $111.31 +/- 0.09, $96.28 +/- 0.44, and $82.21 +/- 1.87, respectively. Polled feeder cattle sold for $118.57 +/- 0.05, and horned feeder cattle sold for $114.87 +/- 0.14 (P <0.001). Interactions (P <0.001) were detected between frame score and BW groups, and muscle score and BW groups on the selling price of cattle. A number of management and genetic factors affected the selling price of feeder cattle.

  8. Measuring the Double Helix

    SciTech Connect

    Mathew-Fenn, R.S.; Das, R.; Harbury, P.A.B.

    2009-05-26

    DNA is thought to behave as a stiff elastic rod with respect to the ubiquitous mechanical deformations inherent to its biology. To test this model at short DNA lengths, we measured the mean and variance of end-to-end length for a series of DNA double helices in solution, using small-angle x-ray scattering interference between gold nanocrystal labels. In the absence of applied tension, DNA is at least one order of magnitude softer than measured by single-molecule stretching experiments. Further, the data rule out the conventional elastic rod model. The variance in end-to-end length follows a quadratic dependence on the number of base pairs rather than the expected linear dependence, indicating that DNA stretching is cooperative over more than two turns of the DNA double helix. Our observations support the idea of long-range allosteric communication through DNA structure.

  9. A Virtual Field Trip to the Real World of Cap and Trade: Environmental Economics and the EPA SO[subscript 2] Allowance Auction

    ERIC Educational Resources Information Center

    Lewis, Lynne Y.

    2011-01-01

    In the spring of 2001, Bates College Environmental Economics classes bought their first sulfur dioxide emissions allowance at U.S. Environmental Protection Agency's annual auction, then conducted by the Chicago Board of Trade. In the spring of 2010, they bought their 22nd through 34th allowances. This article describes a three-part method for…

  10. 31 CFR 356.4 - What are the book-entry systems in which auctioned Treasury securities may be issued or maintained?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 2 2011-07-01 2011-07-01 false What are the book-entry systems in... BUREAU OF THE PUBLIC DEBT SALE AND ISSUE OF MARKETABLE BOOK-ENTRY TREASURY BILLS, NOTES, AND BONDS... book-entry systems in which auctioned Treasury securities may be issued or maintained? There are...

  11. Do I hear... anyone here? Tax-exempt healthcare facilities have taken a hit on auction-rate securities as the mortgage meltdown has investors skittish.

    PubMed

    Evans, Melanie

    2008-02-25

    The crisis in auction-rate securities is coming down hard on tax-exempt providers. Buyers are disappearing, sending interest rates soaring. Some hospitals and other healthcare borrowers are being forced to pay maximum interest. "Basically, the investor pool has all but vanished," says Melissa Williams, left, of Christus Health. PMID:18491765

  12. A revealed preference approach to estimating supply curves for ecosystem services: use of auctions to set payments for soil erosion control in Indonesia.

    PubMed

    Jack, B Kelsey; Leimona, Beria; Ferraro, Paul J

    2009-04-01

    To supply ecosystem services, private landholders incur costs. Knowledge of these costs is critical for the design of conservation-payment programs. Estimating these costs accurately is difficult because the minimum acceptable payment to a potential supplier is private information. We describe how an auction of payment contracts can be designed to elicit this information during the design phase of a conservation-payment program. With an estimate of the ecosystem-service supply curve from a pilot auction, conservation planners can explore the financial, ecological, and socioeconomic consequences of alternative scaled-up programs. We demonstrate the potential of our approach in Indonesia, where soil erosion on coffee farms generates downstream ecological and economic costs. Bid data from a small-scale, uniform-price auction for soil-conservation contracts allowed estimates of the costs of a scaled-up program, the gain from integrating biophysical and economic data to target contracts, and the trade-offs between poverty alleviation and supply of ecosystem services. Our study illustrates an auction-based approach to revealing private information about the costs of supplying ecosystem services. Such information can improve the design of programs devised to protect and enhance ecosystem services.

  13. 78 FR 65982 - Auction of H Block Licenses in the 1915-1920 MHz and 1995-2000 MHz Bands Rescheduled for January...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... Comment Public Notice, 78 FR 45524, July 29, 2013. B. Description of Licenses To Be Offered in Auction 96 4. In the H Block Report and Order, 78 FR 50213, August 16, 2013, the Commission concluded that... violate 47 CFR 1.2105(c), particularly in light of the limited information procedures in effect...

  14. Seeing Double

    NASA Astrophysics Data System (ADS)

    Pesic, Peter

    2003-10-01

    The separateness and connection of individuals is perhaps the central question of human life: What, exactly, is my individuality? To what degree is it unique? To what degree can it be shared, and how? To the many philosophical and literary speculations about these topics over time, modern science has added the curious twist of quantum theory, which requires that the elementary particles of which everything consists have no individuality at all. All aspects of chemistry depend on this lack of individuality, as do many branches of physics. From where, then, does our individuality come? In Seeing Double, Peter Pesic invites readers to explore this intriguing set of questions. He draws on literary and historical examples that open the mind (from Homer to Martin Guerre to Kafka), philosophical analyses that have helped to make our thinking and speech more precise, and scientific work that has enabled us to characterize the phenomena of nature. Though he does not try to be all-inclusive, Pesic presents a broad range of ideas, building toward a specific point of view: that the crux of modern quantum theory is its clash with our ordinary concept of individuality. This represents a departure from the usual understanding of quantum theory. Pesic argues that what is bizarre about quantum theory becomes more intelligible as we reconsider what we mean by individuality and identity in ordinary experience. In turn, quantum identity opens a new perspective on us. Peter Pesic is a Tutor and Musician-in-Residence at St. John's College, Santa Fe, New Mexico. He has a Ph.D. in physics from Stanford University.

  15. Double inflation

    SciTech Connect

    Silk, J.; Turner, M.S.

    1986-04-01

    The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The ..cap omega..-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig.

  16. Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

    NASA Astrophysics Data System (ADS)

    Li, Shuo; Bhushan, Bharat

    2016-08-01

    Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

  17. Colloidal Double Quantum Dots

    PubMed Central

    2016-01-01

    Conspectus Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole–dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single

  18. Possible interstellar formation of glycine through a concerted mechanism: a computational study on the reaction of CH2[double bond, length as m-dash]NH, CO2 and H2.

    PubMed

    Nhlabatsi, Zanele P; Bhasi, Priya; Sitha, Sanyasi

    2016-07-27

    Glycine being the simplest amino acid and also having significant astrobiological implications, has meant that intensive investigations have been carried out in the past, starting from its detection in the interstellar medium (ISM) to analysis of meteorites and cometary samples and laboratory synthesis, as well as computational studies on the possible reaction paths. In this present work quantum chemical calculations have been performed to investigate the possible interstellar formation of glycine via two different paths; (1) in a two-step process via a dihydroxy carbene intermediate and (2) through a one-step concerted mechanism, starting from reactants like CH2[double bond, length as m-dash]NH, CO, CO2, H2O and H2. For the two reactions representing the carbene route, it was observed that the formation of dihydroxy carbene from either CO + H2O or CO2 + H2 is highly endothermic with large barrier heights, whereas the subsequent step of interaction of this carbene with CH2[double bond, length as m-dash]NH to give glycine is exothermic and the barrier is below the reactants. Based on this observation it is suggested that the formation of glycine via the carbene route is a least favourable or even unfavourable path. On the other hand, the two reactions CH2[double bond, length as m-dash]NH + CO + H2O and CH2[double bond, length as m-dash]NH + CO2 + H2 representing the concerted paths were found to be favourable in leading to the formation of glycine. After an extensive study on the first concerted reaction in our previous work (Phys. Chem. Chem. Phys., 2016, 18, 375-381), in this work a detailed investigation has been carried out for the second concerted reaction, CH2[double bond, length as m-dash]NH + CO2 + H2, which can possibly lead to the interstellar formation of glycine. It was observed that this reaction proceeds through a large barrier and at the same time the transition state shows prominent hydrogen dynamics, indicating a tunnelling possibility for this

  19. Possible interstellar formation of glycine through a concerted mechanism: a computational study on the reaction of CH2[double bond, length as m-dash]NH, CO2 and H2.

    PubMed

    Nhlabatsi, Zanele P; Bhasi, Priya; Sitha, Sanyasi

    2016-07-27

    Glycine being the simplest amino acid and also having significant astrobiological implications, has meant that intensive investigations have been carried out in the past, starting from its detection in the interstellar medium (ISM) to analysis of meteorites and cometary samples and laboratory synthesis, as well as computational studies on the possible reaction paths. In this present work quantum chemical calculations have been performed to investigate the possible interstellar formation of glycine via two different paths; (1) in a two-step process via a dihydroxy carbene intermediate and (2) through a one-step concerted mechanism, starting from reactants like CH2[double bond, length as m-dash]NH, CO, CO2, H2O and H2. For the two reactions representing the carbene route, it was observed that the formation of dihydroxy carbene from either CO + H2O or CO2 + H2 is highly endothermic with large barrier heights, whereas the subsequent step of interaction of this carbene with CH2[double bond, length as m-dash]NH to give glycine is exothermic and the barrier is below the reactants. Based on this observation it is suggested that the formation of glycine via the carbene route is a least favourable or even unfavourable path. On the other hand, the two reactions CH2[double bond, length as m-dash]NH + CO + H2O and CH2[double bond, length as m-dash]NH + CO2 + H2 representing the concerted paths were found to be favourable in leading to the formation of glycine. After an extensive study on the first concerted reaction in our previous work (Phys. Chem. Chem. Phys., 2016, 18, 375-381), in this work a detailed investigation has been carried out for the second concerted reaction, CH2[double bond, length as m-dash]NH + CO2 + H2, which can possibly lead to the interstellar formation of glycine. It was observed that this reaction proceeds through a large barrier and at the same time the transition state shows prominent hydrogen dynamics, indicating a tunnelling possibility for this

  20. Target Tracking via Crowdsourcing: A Mechanism Design Approach

    NASA Astrophysics Data System (ADS)

    Cao, Nianxia; Brahma, Swastik; Varshney, Pramod K.

    2015-03-01

    In this paper, we propose a crowdsourcing based framework for myopic target tracking by designing an incentive-compatible mechanism based optimal auction in a wireless sensor network (WSN) containing sensors that are selfish and profit-motivated. For typical WSNs which have limited bandwidth, the fusion center (FC) has to distribute the total number of bits that can be transmitted from the sensors to the FC among the sensors. To accomplish the task, the FC conducts an auction by soliciting bids from the selfish sensors, which reflect how much they value their energy cost. Furthermore, the rationality and truthfulness of the sensors are guaranteed in our model. The final problem is formulated as a multiple-choice knapsack problem (MCKP), which is solved by the dynamic programming method in pseudo-polynomial time. Simulation results show the effectiveness of our proposed approach in terms of both the tracking performance and lifetime of the sensor network.

  1. Investigation of double bond conversion, mechanical properties, and antibacterial activity of dental resins with different alkyl chain length quaternary ammonium methacrylate monomers (QAM).

    PubMed

    He, Jingwei; Söderling, Eva; Vallittu, Pekka K; Lassila, Lippo V J

    2013-01-01

    In order to endow dental resin with antibacterial activity, a series of antibacterial quaternary ammonium methacrylate monomers (QAM) with different substituted alkyl chain length (from 10 to 18) were incorporated into commonly used 2,2-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]propane (Bis-GMA)/triethyleneglycol dimethacrylate (TEGDMA) (50 wt/50 wt) dental resin as immobilized antibacterial agents. Double bond conversion (DC), flexural strength (FS) and modulus (FM), and young and mature biofilms inhibition effectiveness of prepared dental resins were studied and Bis-GMA/TEGDMA without QAM was used as reference. Results showed that there was no significant difference on DC, FS, and FM between copolymer with and without 5 wt% QAM. Substituted alkyl chain length of QAM had no influence on DC, FS, and FM of copolymer, but had influence on antibacterial activity of copolymer. Antibacterial activity of copolymer increased with increasing of substituted alkyl chain length of QAM, and the sequence followed as 5%C10 < 5%C11 ≈ 5%C12 < 5%C16 ≈ 5%C18. Copolymers containing C18 and C16 had the best inhibition effectiveness on both young biofilm and mature biofilm, copolymers containing C12 and C11 only had inhibition effectiveness on young biofilm and copolymer containing C10 had none inhibition effectiveness on neither young biofilm nor mature biofilm.

  2. Chromium (VI) and zinc (II) waste water co-treatment by forming layered double hydroxides: mechanism discussion via two different processes and application in real plating water.

    PubMed

    Zhang, Jia; Li, Yang; Zhou, Jizhi; Chen, Dan; Qian, Guangren

    2012-02-29

    Two processes, adsorption after synthesis (AAS) and adsorption during synthesis (ADS) were compared in CrO4(2-) and Zn2+/CrO4(2-) removal. Kinetic results showed that ADS was a better method than AAS, since Cr content was 0.65/0.81 mmol/g in Cr-ADS/ZnCr-ADS, but it was only 0.37/0.56 mmol/g in Cr-AAS/ZnCr-AAS. Then, a low-cost mixture was proposed to function as ADS raw materials in treating real plating waters. This mixture first got an isothermal saturation of 1.1 mmol/g in simulated CrO4(2-) water. When Zn2+ was co-treated, it was increased to 1.3 mmol/g. At the same time, a Zn2+ removal of 1.5 mmol/g was attained. Furthermore, real plating water co-treatment reached equilibrium in 6h and obtained 1.4/0.9 mmol/g for Zn2+/CrO4(2-), respectively. According to XRD analysis, this co-treatment enhancement resulted from the formation of Zn and Cr contained layered double hydroxide.

  3. Biphoton double-slit experiment

    SciTech Connect

    Brida, G.; Cagliero, E.; Falzetta, G.; Genovese, M.; Gramegna, M.; Predazzi, E.

    2003-09-01

    In this paper we present a double-slit experiment where two indistinguishable photons produced by type-I parametric down-conversion are each sent to a well-defined slit. Data about the diffraction and interference patterns for coincidences are presented and discussed. An analysis of these data allows a test of standard quantum mechanics against the de Broglie-Bohm theory.

  4. Natural products: DNA double whammy

    NASA Astrophysics Data System (ADS)

    Gates, Kent S.

    2014-06-01

    The lomaiviticins are exceedingly potent antibiotic agents, but the mechanism responsible for this activity has so far been unclear. Now, efficient generation of double-strand breaks in DNA by lomaiviticin A has been linked to the remarkable cytotoxicity of these diazobenzofluorene-containg natural products.

  5. Effect of amino acid dopants on the spectral, optical, mechanical and thermal properties of potassium acid phthalate crystals for possible optoelectronic and frequency doubling applications

    NASA Astrophysics Data System (ADS)

    Prakash, J. Thomas Joseph; Gnanaraj, J. Martin Sam; Dhavud, S. Shek; Ekadevasena, S.

    2015-09-01

    Undoped and amino acid (L-Arginine and L-Valine) doped KAP crystals were grown by slow evaporation solution growth technique. The changes in the structural, spectral, optical, mechanical and thermal properties were observed. The sharp prominent peaks in the indexed powder XRD pattern confirms the crystalline nature of the sample. Optical studies reveal that the crystal is transparent in the entire visible light region. Thermal stability was checked by TG/DTA analysis. The mechanical stability was evaluated from Vicker's microhardness test. The SHG efficiency for the title materials was tested with different particle sizes by the Kurtz and Perry powder method, which established the existence of phase matching.

  6. The double loop mattress suture

    PubMed Central

    Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

    2014-01-01

    An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p ≤ 0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p ≤ 0.001). Wound gapping is equal, and wound eversion appears significantly improved (p ≤ 0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

  7. Gene expression suggests double-segmental and single-segmental patterning mechanisms during posterior segment addition in the beetle Tribolium castaneum.

    PubMed

    Janssen, Ralf

    2014-01-01

    In the model arthropod Drosophila, all segments are patterned simultaneously in the blastoderm. In most other arthropods, however, posterior segments are added sequentially from a posterior segment addition zone. Posterior addition of single segments likely represents the ancestral mode of arthropod segmentation, although in Drosophila, segments are patterned in pairs by the pair-rule genes. It has been shown that in the new model insect, the beetle Tribolium, a segmentation clock operates that apparently patterns all segments in pairs as well. Here, I report on the expression of the segment polarity gene H15/midline in Tribolium. In the anterior embryo, segmental stripes of H15 appear in pairs, but in the posterior of the embryo stripes appear in a single-segmental periodicity. This implies that either two completely different segmentation-mechanisms may act in the germ band of Tribolium, that the segmentation clock changes its periodicity during development, or that the speed in which posterior segments are patterned changes. In any case, the data suggest the presence of another (or modified), yet undiscovered, mechanism of posterior segment addition in one of the best-understood arthropod models. The finding of a hitherto unrecognized segmentation mechanism in Tribolium may have major implications for the understanding of the origin of segmentation mechanisms, including the origin of pair rule patterning. It also calls for (re)-investigation of posterior segment addition in Tribolium and other previously studied arthropod models.

  8. Nature and possible mechanisms of formation of potential mutations arising at emerging of thymine dimers after irradiation of double-stranded DNA by ultraviolet light

    NASA Astrophysics Data System (ADS)

    Grebneva, H. A.

    2003-01-01

    The mutagenesis under ultraviolet (UV)-irradiation is discussed. It is assumed, that the basic damages resulting in transitions, transversions, mutations of the frameshift and complex mutations are changes of the tautomeric state of the bases. The bases may be a part of dimers or may be not the dimer components. We consider such rare tautomeric states, which may influence the character of base pairing. A model of the formation of the above rare tautomeric forms of nucleotide bases under the UV-irradiation of the DNA is proposed. In the case of a radiation deexcitation of the DNA, which has absorbed the UV-quantum of the triplet energy level, there occur strong forced oscillations. They may result in changes of the lengths of hydrogen bonds between DNA bases. As a result, at H-bond shortening, the hydrogen atom may be almost in the center of H-bond. In the case of H-bond elongation, it may remain near the partner atom. Because of the H-bond breaking, during the formation of dimers, rare tautomeric forms of bases influencing the character of pairing can be realized. If a pair of the bases is not a part of dimer, then the only new stable configuration of the hydrogen atoms is the one that occurred at double-proton phototautomerism. It is shown that only those dimers are mutational, in which the change of a tautomeric state of the DNA bases have taken place. This is one of the differences between the proposed model and the standard one. The latter assumes, that from the point of view of ability of forming the mutations all the dimers are identical, and the DNA-polymerase is sometimes mistaken, incidentally building uncomplementary bases in. The consideration is only of qualitative character, it needs experimental verification, subsequent study by methods of quantum chemistry and theoretical physics. A list of problems to be studied in this respect is given.

  9. Mechanisms Regulating Insulin Response to Intragastric Glucose in Lean and Non-Diabetic Obese Subjects: A Randomized, Double-Blind, Parallel-Group Trial

    PubMed Central

    Meyer-Gerspach, Anne Christin; Cajacob, Lucian; Riva, Daniele; Herzog, Raphael; Drewe, Juergen; Beglinger, Christoph; Wölnerhanssen, Bettina K.

    2016-01-01

    Background/Objectives The changes in blood glucose concentrations that result from an oral glucose challenge are dependent on the rate of gastric emptying, the rate of glucose absorption and the rate of insulin-driven metabolism that include the incretins, glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). The rate of insulin-driven metabolism is clearly altered in obese subjects, but it is controversial which of these factors is predominant. We aimed to quantify gastric emptying, plasma insulin, C-peptide, glucagon and glucose responses, as well as incretin hormone secretions in obese subjects and healthy controls during increasing glucose loads. Subjects/Methods The study was conducted as a randomized, double-blind, parallel-group trial in a hospital research unit. A total of 12 normal weight (6 men and 6 women) and 12 non-diabetic obese (BMI > 30, 6 men and 6 women) participants took part in the study. Subjects received intragastric loads of 10 g, 25 g and 75 g glucose dissolved in 300 ml tap water. Results Main outcome measures were plasma GLP-1 and GIP, plasma glucagon, glucose, insulin, C-peptide and gastric emptying. The primary findings are: i) insulin resistance (P < 0.001) and hyperinsulinemia (P < 0.001); ii) decreased insulin disposal (P < 0.001); iii) trend for reduced GLP-1 responses at 75 g glucose; and iv) increased fasting glucagon levels (P < 0.001) in obese subjects. Conclusions It seems that, rather than changes in incretin secretion, fasting hyperglucagonemia and consequent hyperglycemia play a role in reduced disposal of insulin, contributing to hyperinsulinemia and insulin resistance. Trial Registration ClinicalTrials.gov NCT01875575 PMID:26942445

  10. [The application of n-acetylcysteine as an antioxidant and mucolytic in mechanical ventilation in intensive care patients. A prospective, randomized, placebo-controlled, double-blind study].

    PubMed

    Konrad, F; Schoenberg, M H; Wiedmann, H; Kilian, J; Georgieff, M

    1995-09-01

    Oxygen radicals and oxygen radial mediators are thought to be important components in the development of acute lung injury, sepsis, and multiple organ failure. Injured patients, patients with pulmonary diseases, and multiple trauma patients also showed an elevated lipid peroxidation, indicating increased oxidant stress. N-Acetylcysteine (NAC) has been used as an antioxidant in a wide variety of experiments. NAC has been suggested to act by raising concentrations of cysteine, and hence glutathione, and by scavenging of oxidant species [1, 11, 17, 29]. The present study was designed to investigate whether the application of NAC in intubated patients has an effect on concentrations of reduced glutathione in plasma and bronchoalveolar lavage fluid (BAL) and on the lipid peroxidation products malondialdehyde and conjugated dienes. Because NAC has been widely used as a mucolytic drug for the treatment of lung diseases, the influence on tracheobronchial mucus was studied, too. METHODS. In a randomized, double-blind, placebo-controlled study, a total of 38 long-term ventilated patients of a surgical intensive care unit were investigated. Patients were treated for 5 days with either 3 g NAC/day or placebo. The plasma concentration of reduced glutathione, malondialdehyde, and conjugated dienes were measured on admission and on the 3rd and 5th days of treatment [8, 34, 48]. Additionally, the numbers of tracheobronchial suctionings were registered and chest radiographs were evaluated. A fibre-bronchoscopy was performed on admission and on the 3rd day of treatment. The amount and viscidity of tracheobronchial secretions were examined semiquantitatively, and glutathione levels were measured in the unconcentrated BAL. The study was approved by the ethics committee of the University of Ulm. RESULTS. The two groups were comparable with respect to age, sex, APACHE II score and diagnosis (Table 1). We found no significant differences in reduced glutathione levels in the plasma or in

  11. Mechanism of action studies of lomaiviticin A and the monomeric lomaiviticin aglycon. Selective and potent activity toward DNA double-strand break repair-deficient cell lines.

    PubMed

    Colis, Laureen C; Hegan, Denise C; Kaneko, Miho; Glazer, Peter M; Herzon, Seth B

    2015-05-01

    (-)-Lomaiviticin A (1) and the monomeric lomaiviticin aglycon [aka: (-)-MK7-206, (3)] are cytotoxic agents that induce double-strand breaks (DSBs) in DNA. Here we elucidate the cellular responses to these agents and identify synthetic lethal interactions with specific DNA repair factors. Toward this end, we first characterized the kinetics of DNA damage by 1 and 3 in human chronic myelogenous leukemia (K562) cells. DSBs are rapidly induced by 3, reaching a maximum at 15 min post addition and are resolved within 4 h. By comparison, DSB production by 1 requires 2-4 h to achieve maximal values and >8 h to achieve resolution. As evidenced by an alkaline comet unwinding assay, 3 induces extensive DNA damage, suggesting that the observed DSBs arise from closely spaced single-strand breaks (SSBs). Both 1 and 3 induce ataxia telangiectasia mutated- (ATM-) and DNA-dependent protein kinase- (DNA-PK-) dependent production of phospho-SER139-histone H2AX (γH2AX) and generation of p53 binding protein 1 (53BP1) foci in K562 cells within 1 h of exposure, which is indicative of activation of nonhomologous end joining (NHEJ) and homologous recombination (HR) repair. Both compounds also lead to ataxia telangiectasia and Rad3-related- (ATR-) dependent production of γH2AX at later time points (6 h post addition), which is indicative of replication stress. 3 is also shown to induce apoptosis. In accord with these data, 1 and 3 were found to be synthetic lethal with certain mutations in DNA DSB repair. 1 potently inhibits the growth of breast cancer type 2, early onset- (BRCA2-) deficient V79 Chinese hamster lung fibroblast cell line derivative (VC8), and phosphatase and tensin homologue deleted on chromosome ten- (PTEN-) deficient human glioblastoma (U251) cell lines, with LC50 values of 1.5 ± 0.5 and 2.0 ± 0.6 pM, respectively, and selectivities of >11.6 versus the isogenic cell lines transfected with and expressing functional BRCA2 and PTEN genes. 3 inhibits the growth of the same

  12. [The application of n-acetylcysteine as an antioxidant and mucolytic in mechanical ventilation in intensive care patients. A prospective, randomized, placebo-controlled, double-blind study].

    PubMed

    Konrad, F; Schoenberg, M H; Wiedmann, H; Kilian, J; Georgieff, M

    1995-09-01

    Oxygen radicals and oxygen radial mediators are thought to be important components in the development of acute lung injury, sepsis, and multiple organ failure. Injured patients, patients with pulmonary diseases, and multiple trauma patients also showed an elevated lipid peroxidation, indicating increased oxidant stress. N-Acetylcysteine (NAC) has been used as an antioxidant in a wide variety of experiments. NAC has been suggested to act by raising concentrations of cysteine, and hence glutathione, and by scavenging of oxidant species [1, 11, 17, 29]. The present study was designed to investigate whether the application of NAC in intubated patients has an effect on concentrations of reduced glutathione in plasma and bronchoalveolar lavage fluid (BAL) and on the lipid peroxidation products malondialdehyde and conjugated dienes. Because NAC has been widely used as a mucolytic drug for the treatment of lung diseases, the influence on tracheobronchial mucus was studied, too. METHODS. In a randomized, double-blind, placebo-controlled study, a total of 38 long-term ventilated patients of a surgical intensive care unit were investigated. Patients were treated for 5 days with either 3 g NAC/day or placebo. The plasma concentration of reduced glutathione, malondialdehyde, and conjugated dienes were measured on admission and on the 3rd and 5th days of treatment [8, 34, 48]. Additionally, the numbers of tracheobronchial suctionings were registered and chest radiographs were evaluated. A fibre-bronchoscopy was performed on admission and on the 3rd day of treatment. The amount and viscidity of tracheobronchial secretions were examined semiquantitatively, and glutathione levels were measured in the unconcentrated BAL. The study was approved by the ethics committee of the University of Ulm. RESULTS. The two groups were comparable with respect to age, sex, APACHE II score and diagnosis (Table 1). We found no significant differences in reduced glutathione levels in the plasma or in

  13. Responses to the advanced notice of proposed rulemaking EPA published on June 6, 1996 regarding changes to the EPA allowance auctions and elimination of the direct sale

    SciTech Connect

    Critchfield, L.R.

    1997-12-31

    On June 6, 1996, EPA`s Acid Rain Program published an advance notice of proposed rulemaking (ANPRM) in the Federal Register seeking comment on: (1) whether to change the design of the annual sulfur dioxide (SO{sub 2}) allowance auctions; (2) whether to change the timing of the allowance auctions; (3) whether to change the requirement that the minimum price of offered allowances must be in whole dollars, and (4) whether EPA should propose the ability to submit allowance transfers electronically. EPA also published on that day a proposed and direct final rule on whether to eliminate the direct sale. This paper documents the issues addressed in the ANPRM, the comments EPA received, and EPA`s responses to those comments. EPA received comments from 14 separate commenters.

  14. Double universality of a quantum phase transition in spinor condensates: modification of the Kibble-Żurek mechanism by a conservation law.

    PubMed

    Świsłocki, Tomasz; Witkowska, Emilia; Dziarmaga, Jacek; Matuszewski, Michał

    2013-01-25

    We consider a phase transition from an antiferromagnetic to a phase separated ground state in a spin-1 Bose-Einstein condensate of ultracold atoms. We demonstrate the occurrence of two scaling laws, for the number of spin domain seeds just after the phase transition, and for the number of spin domains in the final, stable configuration. Only the first scaling can be explained by the standard Kibble-Żurek mechanism. We explain the occurrence of two scaling laws by a model including postselection of spin domains due to the conservation of condensate magnetization.

  15. Dynamical aspects of electrostatic double layers

    NASA Astrophysics Data System (ADS)

    Raadu, Michael A.; Rasmussen, J. Juul

    1988-05-01

    Electrostatic double layers have been proposed as an acceleration mechanism in solar flares and other astrophysical objects. They have been extensively studied in the laboratory and by means of computer simulations. The theory of steady-state double layers implies several existence criteria, in particular the Bohm criteria, restricting the conditions under which double layers may form. In the present paper several already published theoretical models of different types of double layers are discussed. It is shown that the existence conditions often imply current-driven instabilities in the ambient plasma, at least for strong double layers, and it is argued that such conditions must be used with care when applied to real plasmas. Laboratory double layers, and by implication those arising in astrophysical plasmas, often produce instabilities in the surrounding plasma and are generally time-dependent structures. Naturally occurring double layers should therefore, be far more common than the restrictions deduced from idealized time-independent models would imply. In particular it is necessary to understand more fully the time-dependent behavior of double layers. In the present paper the dynamics of weak double layers is discussed. Also a model for moving a strong double layer, where an associated potential minimum plays a significant role, is presented.

  16. Estimating the impact of various menu labeling formats on parents' demand for fast-food kids' meals for their children: An experimental auction.

    PubMed

    Hobin, Erin; Lillico, Heather; Zuo, Fei; Sacco, Jocelyn; Rosella, Laura; Hammond, David

    2016-10-01

    This study experimentally tested whether parents' demand for fast-food kids' meals for their children is influenced by various menu labeling formats disclosing calorie and sodium information. The study also examined the effect of various menu labeling formats on parents' ability to identify fast-food kids' meals with higher calorie and sodium content. Online surveys were conducted among parents of children aged 3-12. Parents were randomized to view 1 of 5 menu conditions: 1) No Nutrition Information; 2) Calories-Only; 3) Calories + Contextual Statement (CS); 4) Calories, Sodium, + CS; and, 5) Calorie and Sodium in Traffic Lights + CS. Using an established experimental auction study design, parents viewed replicated McDonald's menus according to their assigned condition and were asked to bid on 4 Happy Meals. A randomly selected price was chosen; bids equal to or above this price "won" the auction, and bids less than this price "lost" the auction. After the auction, participants were asked to identify the Happy Meal with the highest calories and sodium content. Adjusting for multiple comparisons and covariates, the Calories, Sodium, + CS menu had a mean attributed value across all 4 Happy Meals which was 8% lower (-$0.31) than the Calories + CS menu (p < 0.05). Significantly more parents in the 4 menu conditions providing calories were able to correctly identify the Happy Meal with the highest calories (p < 0.0001) and significantly more parents in the 2 conditions providing sodium information were able to correctly identify the Happy Meal with the highest sodium content (p < 0.0001). Menus disclosing both calories and sodium information may reduce demand for fast-food kids' meals and better support parents in making more informed and healthier food choices for their children. PMID:27317971

  17. Estimating the impact of various menu labeling formats on parents' demand for fast-food kids' meals for their children: An experimental auction.

    PubMed

    Hobin, Erin; Lillico, Heather; Zuo, Fei; Sacco, Jocelyn; Rosella, Laura; Hammond, David

    2016-10-01

    This study experimentally tested whether parents' demand for fast-food kids' meals for their children is influenced by various menu labeling formats disclosing calorie and sodium information. The study also examined the effect of various menu labeling formats on parents' ability to identify fast-food kids' meals with higher calorie and sodium content. Online surveys were conducted among parents of children aged 3-12. Parents were randomized to view 1 of 5 menu conditions: 1) No Nutrition Information; 2) Calories-Only; 3) Calories + Contextual Statement (CS); 4) Calories, Sodium, + CS; and, 5) Calorie and Sodium in Traffic Lights + CS. Using an established experimental auction study design, parents viewed replicated McDonald's menus according to their assigned condition and were asked to bid on 4 Happy Meals. A randomly selected price was chosen; bids equal to or above this price "won" the auction, and bids less than this price "lost" the auction. After the auction, participants were asked to identify the Happy Meal with the highest calories and sodium content. Adjusting for multiple comparisons and covariates, the Calories, Sodium, + CS menu had a mean attributed value across all 4 Happy Meals which was 8% lower (-$0.31) than the Calories + CS menu (p < 0.05). Significantly more parents in the 4 menu conditions providing calories were able to correctly identify the Happy Meal with the highest calories (p < 0.0001) and significantly more parents in the 2 conditions providing sodium information were able to correctly identify the Happy Meal with the highest sodium content (p < 0.0001). Menus disclosing both calories and sodium information may reduce demand for fast-food kids' meals and better support parents in making more informed and healthier food choices for their children.

  18. [Current status of illegal trade in pharmaceutical products on Internet auction sites in Japan and responses of site administrators to such transactions].

    PubMed

    Ohtani, Hisakazu; Imaoka, Ayuko; Akiyoshi, Takeshi

    2015-01-01

    In Japan, it is illegal to sell pharmaceuticals on Internet auction sites, although a considerable number of pharmaceuticals are listed on such sites. We investigated the current situation regarding the illegal trade in pharmaceuticals on Japanese Internet auction sites and the responses of site administrators to such transactions. We searched for pharmaceuticals and "gray" items that were suspected of being pharmaceuticals on Yahoo-oku! (Yahoo! Auctions, Japan) over a 37-day period and then submitted violation reports indicating that selling pharmaceuticals is illegal or that the description of an item was insufficient. The reports were directed to the site administrators and forwarded to the sellers. One hundred and six pharmaceutical products and 34 gray items were identified during the study period. After the submission of the violation reports, only 28 of the pharmaceutical products and one of the gray items were deleted by the administrator, while 18 of the pharmaceutical products and 7 of the gray items were withdrawn by their sellers. However, 41 pharmaceuticals and 20 gray items were sold. Most of the gray items were listed using characteristic terms or abbreviations without photographic images. More than 70% of the identified pharmaceuticals had a contraindication(s) other than hypersensitivity. In conclusion, the illegal trade in pharmaceuticals on Internet auction sites remains a serious problem in Japan, and the responses of site administrators to such transactions are inadequate. The government and pharmaceutical industry may have to take measures such as providing public and administrative guidance to stop the illegal trade in pharmaceuticals on the Internet.

  19. Examining the relationship between psychosocial and behavioral proxies for future consumption behavior: self-reported impact and bidding behavior in an experimental auction study on cigarette labeling

    PubMed Central

    Rousu, Matthew C.; Thrasher, James F.

    2014-01-01

    Experimental and observational research often involves asking consumers to self-report the impact of some proposed option. Because self-reported responses involve no consequence to the respondent for falsely revealing how he or she feels about an issue, self-reports may be subject to social desirability and other influences that bias responses in important ways. In this article, we analyzed data from an experiment on the impact of cigarette packaging and pack warnings, comparing smokers’ self-reported impact (four-item scale) and the bids they placed in experimental auctions to estimate differences in demand. The results were consistent across methods; however, the estimated effect size associated with different warning labels was two times greater for the four-item self-reported response scale when compared to the change in demand as indicated by auction bids. Our study provides evidence that self-reported psychosocial responses provide a valid proxy for behavioral change as reflected by experimental auction bidding behavior. More research is needed to better understand the advantages and disadvantages of behavioral economic methods and traditional self-report approaches to evaluating health behavior change interventions. PMID:24399267

  20. Examining the relationship between psychosocial and behavioral proxies for future consumption behavior: self-reported impact and bidding behavior in an experimental auction study on cigarette labeling.

    PubMed

    Rousu, Matthew C; Thrasher, James F

    2014-04-01

    Experimental and observational research often involves asking consumers to self-report the impact of some proposed option. Because self-reported responses involve no consequence to the respondent for falsely revealing how he or she feels about an issue, self-reports may be subject to social desirability and other influences that bias responses in important ways. In this article, we analyzed data from an experiment on the impact of cigarette packaging and pack warnings, comparing smokers' self-reported impact (four-item scale) and the bids they placed in experimental auctions to estimate differences in demand. The results were consistent across methods; however, the estimated effect size associated with different warning labels was two times greater for the four-item self-reported response scale when compared to the change in demand as indicated by auction bids. Our study provides evidence that self-reported psychosocial responses provide a valid proxy for behavioral change as reflected by experimental auction bidding behavior. More research is needed to better understand the advantages and disadvantages of behavioral economic methods and traditional self-report approaches to evaluating health behavior change interventions. PMID:24399267

  1. A double-double/double-single computation package

    2004-12-01

    The DDFUNIDSFUN software permits a new or existing Fortran-90 program to utilize double-double precision (approx. 31 digits) or double-single precision (approx. 14 digits) arithmetic. Double-double precision is required by a rapidly expandirtg body of scientific computations in physics and mathematics, for which the conventional 64-bit IEEE computer arithmetic (about 16 decimal digit accuracy) is not sufficient. Double-single precision permits users of systems that do not have hardware 64-bit IEEE arithmetic (such as some game systems)more » to perform arithmetic at a precision nearly as high as that of systems that do. Both packages run significantly faster Than using multiple precision or arbitrary precision software for this purpose. The package includes an extensive set of low-level routines to perform high-precision arithmetic, including routines to calculate various algebraic and transcendental functions, such as square roots, sin, ccc, exp, log and others. In addition, the package includes high-level translation facilities, so that Fortran programs can utilize these facilities by making only a few changes to conventional Fortran programs. In most cases, the only changes that are required are to change the type statements of variables that one wishes to be treated as multiple precision, plus a few other minor changes. The DDFUN package is similar in functionality to the double-double part of the GD package, which was previously written at LBNL. However, the DDFUN package is written exclusively in Fortran-90, thus avoidIng difficulties that some users experience when using GD, which includes both Fortran-90 and C++ code.« less

  2. A randomized, double blind, placebo controlled, cross over study to evaluate the analgesic activity of Boswellia serrata in healthy volunteers using mechanical pain model

    PubMed Central

    Prabhavathi, K.; Chandra, U. Shobha Jagdish; Soanker, Radhika; Rani, P. Usha

    2014-01-01

    Objective: Experimental pain models in human healthy volunteers are advantageous for early evaluation of analgesics. All efforts to develop nonsteroidal anti-inflammatory drugs (NSAIDs) which are devoid of gastrointestinal and cardiovascular system effects are still far from achieving a breakthrough. Hence we evaluated the analgesic activity of an ayurvedic drug, Boswellia serrata by using validated human pain models which has shown its analgesic activity both in-vitro and preclinical studies to evaluate the analgesic activity of single oral dose (125 mg, 2 capsules) of Boswellia serrata compared to placebo using mechanical pain model in healthy human subjects. Materials and Methods: After taking written informed consent, twelve healthy subjects were randomized (1:1) to receive single oral dose of Boswellia serrata (Shallaki®) 125 mg, 2 capsules or identical placebo in a crossover design. Mechanical pain was assessed using Ugo basile analgesymeter (by Randall Selitto test) at baseline and at 1 hr, 2 hrs and 3 hrs after test drug administration. Pain Threshold force and time and Pain Tolerance force and time were evaluated. Statistical analysis was done by paired t-test. Results: Twelve healthy volunteers have completed the study. Mean percentage change from baseline in Pain Threshold force and time with Boswellia serrata when compared to placebo had significantly increased [Force: 9.7 ± 11.0 vs 2.9 ± 3.4 (P = 0.05) and time: 9.7 ± 10.7 vs 2.8 ± 3.4 (P = 0.04)] at third hr. Mean Percentage change from baseline in Pain Tolerance force and time with Boswellia serrata when compared to placebo had significantly (P ≤ 0.01) increased at 1 hr, 2 hrs and 3 hrs. Conclusion: In the present study, Boswellia serrata significantly increased the Pain Threshold and Pain Tolerance force and time compared to placebo. Both study medications were well tolerated. Further multiple dose studies may be needed to establish the analgesic efficacy of the drug. PMID:25298573

  3. The Cambridge Double Star Atlas

    NASA Astrophysics Data System (ADS)

    MacEvoy, Bruce; Tirion, Wil

    2015-12-01

    Preface; What are double stars?; The binary orbit; Double star dynamics; Stellar mass and the binary life cycle; The double star population; Detecting double stars; Double star catalogs; Telescope optics; Preparing to observe; Helpful accessories; Viewing challenges; Next steps; Appendices: target list; Useful formulas; Double star orbits; Double star catalogs; The Greek alphabet.

  4. Pathways to doubled haploidy: chromosome doubling during androgenesis.

    PubMed

    Seguí-Simarro, J M; Nuez, F

    2008-01-01

    Production of doubled haploid (DH) plants through androgenesis induction is a promising and convenient alternative to conventional selfing techniques for the generation of pure lines for breeding programs. This process comprises two main steps: induction of androgenesis and duplication of the haploid genome. Such duplication is sometimes indirectly induced by the treatments used to promote androgenic development. But usually, an additional step of direct chromosome doubling must be included in the protocol. Duplication of the haploid genome of androgenic individuals has been thought to occur through three mechanisms: endoreduplication, nuclear fusion and c-mitosis. In this review we will revise and analyze the evidences supporting each of the proposed mechanisms and their relevance during androgenesis induction, embryo/callus development and plant regeneration. Special attention will be devoted to nuclear fusion, whose evidences are accumulating in the last years.

  5. Double outlet right ventricle

    MedlinePlus

    ... medlineplus.gov/ency/article/007328.htm Double outlet right ventricle To use the sharing features on this page, please enable JavaScript. Double outlet right ventricle (DORV) is a heart disease that is ...

  6. Chromosome doubling method

    DOEpatents

    Kato, Akio

    2006-11-14

    The invention provides methods for chromosome doubling in plants. The technique overcomes the low yields of doubled progeny associated with the use of prior techniques for doubling chromosomes in plants such as grasses. The technique can be used in large scale applications and has been demonstrated to be highly effective in maize. Following treatment in accordance with the invention, plants remain amenable to self fertilization, thereby allowing the efficient isolation of doubled progeny plants.

  7. Magneto-conductive mechanisms in the La-site doped double-layered La1.4Ca1.6Mn2O7 manganites

    NASA Astrophysics Data System (ADS)

    Mahamdioua, N.; Amira, A.; Boudjadja, Y.; Saoudel, A.; Altintas, S. P.; Varilci, A.; Terzioglu, C.

    2016-11-01

    Magneto-conductive mechanisms and properties of La1.2Re0.2Ca1.6Mn2O7 (Re=La, Pr, Y, Gd and Eu) have been investigated. In the low temperature range, combining residual resistivity, weak localization effect, electron-electron and electron-phonon interactions in a model, fit well the resistivity curves of undoped, Pr-doped and Y-doped samples. The Gd-doped and Eu-doped ones require the introduction of the small polaron metallic conduction. In the high temperature range, 3D-Mott's variable range hopping (3D-VRH) is the best model to fit resistivity of the undoped, Pr-doped and Y-doped samples, while Effros-Shklovskii model (ES-VRH) is the best one for Gd-doped and Eu-doped samples. In the entire temperature range, the percolation model fit well the resistivity. Using 3D-VRH model, the density of state (DOS) decreases with doping by Gd and Eu, whereas mean hopping distance Rh(T) and mean hopping energy Eh(T) increase. This may explain the resistivity increase and the crossover to the ES-VRH model. Values of Rh(T) vary between 1.811 and 1.030 nm, which allow us to suggest 3D-VRH as the best model fitting current results. Eh(T) values range from 0.1157 to 0.2635 eV. The DOS increases as increasing magnetic field while Rh(T) and Eh(T) decrease, which is in agreement with the observed decrease of resistivity.

  8. Explanation by the double-metal-ion mechanism of catalysis for the differential metal ion effects on the cleavage rates of 5′-oxy and 5′-thio substrates by a hammerhead ribozyme

    PubMed Central

    Zhou, De-Min; Zhang, Li-He; Taira, Kazunari

    1997-01-01

    In a previous examination using natural all-RNA substrates that contained either a 5′-oxy or 5′-thio leaving group at the cleavage site, we demonstrated that (i) the attack by the 2′-oxygen at C17 on the phosphorus atom is the rate-limiting step only for the substrate that contains a 5′-thio group (R11S) and (ii) the departure of the 5′ leaving group is the rate-limiting step for the natural all-RNA substrate (R11O) in both nonenzymatic and hammerhead ribozyme-catalyzed reactions; the energy diagrams for these reactions were provided in our previous publication. In this report we found that the rate of cleavage of R11O by a hammerhead ribozyme was enhanced 14-fold when Mg2+ ions were replaced by Mn2+ ions, whereas the rate of cleavage of R11S was enhanced only 2.2-fold when Mg2+ ions were replaced by Mn2+ ions. This result appears to be exactly the opposite of that predicted from the direct coordination of the metal ion with the leaving 5′-oxygen, because a switch in metal ion specificity was not observed with the 5′-thio substrate. However, our quantitative analyses based on the previously provided energy diagram indicate that this result is in accord with the double-metal-ion mechanism of catalysis. PMID:9405614

  9. Cardiovascular risk and mortality in end-stage renal disease patients undergoing dialysis: sleep study, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life: a prospective, double blind, randomized controlled clinical trial

    PubMed Central

    2013-01-01

    Background Chronic kidney disease (CKD) is one of the most serious public health problems. The increasing prevalence of CKD in developed and developing countries has led to a global epidemic. The hypothesis proposed is that patients undergoing dialysis would experience a marked negative influence on physiological variables of sleep and autonomic nervous system activity, compromising quality of life. Methods/Design A prospective, consecutive, double blind, randomized controlled clinical trial is proposed to address the effect of dialysis on sleep, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life in patients with CKD. The measurement protocol will include body weight (kg); height (cm); body mass index calculated as weight/height2; circumferences (cm) of the neck, waist, and hip; heart and respiratory rates; blood pressures; Mallampati index; tonsil index; heart rate variability; maximum ventilatory pressures; negative expiratory pressure test, and polysomnography (sleep study), as well as the administration of specific questionnaires addressing sleep apnea, excessive daytime sleepiness, depression, anxiety, stress, and quality of life. Discussion CKD is a major public health problem worldwide, and its incidence has increased in part by the increased life expectancy and increasing number of cases of diabetes mellitus and hypertension. Sleep disorders are common in patients with renal insufficiency. Our hypothesis is that the weather weight gain due to volume overload observed during interdialytic period will influence the degree of collapsibility of the upper airway due to narrowing and predispose to upper airway occlusion during sleep, and to investigate the negative influences of haemodialysis in the physiological variables of sleep, and autonomic nervous system, and respiratory mechanics and thereby compromise the quality of life of patients. Trial registration The

  10. Encouraging stormwater management using a reverse auction: potential to restore stream ecosystems

    EPA Science Inventory

    Stormwater runoff is the primary mechanism by which urbanizing landscapes disrupt natural, stream ecosystems. Source control management has been demonstrated as an effective and cost-efficient method for reducing stormwater runoff; however, sufficiently widespread implementation...

  11. Electric fields and double layers in plasmas

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra; Thiemann, H.; Schunk, R. W.

    1987-01-01

    Various mechanisms for driving double layers in plasmas are briefly described, including applied potential drops, currents, contact potentials, and plasma expansions. Some dynamical features of the double layers are discussed. These features, as seen in simulations, laboratory experiments, and theory, indicate that double layers and the currents through them undergo slow oscillations which are determined by the ion transit time across an effective length of the system in which double layers form. It is shown that a localized potential dip forms at the low potential end of a double layer, which interrupts the electron current through it according to the Langmuir criterion, whenever the ion flux into the double is disrupted. The generation of electric fields perpendicular to the ambient magnetic field by contact potentials is also discussed. Two different situations were considered; in one, a low-density hot plasma is sandwiched between high-density cold plasmas, while in the other a high-density current sheet permeates a low-density background plasma. Perpendicular electric fields develop near the contact surfaces. In the case of the current sheet, the creation of parallel electric fields and the formation of double layers are also discussed when the current sheet thickness is varied. Finally, the generation of electric fields and double layers in an expanding plasma is discussed.

  12. Negative Coulomb Drag in Double Bilayer Graphene.

    PubMed

    Li, J I A; Taniguchi, T; Watanabe, K; Hone, J; Levchenko, A; Dean, C R

    2016-07-22

    We report on an experimental measurement of Coulomb drag in a double quantum well structure consisting of bilayer-bilayer graphene, separated by few layer hexagonal boron nitride. At low temperatures and intermediate densities, a novel negative drag response with an inverse sign is observed, distinct from the momentum and energy drag mechanisms previously reported in double monolayer graphene. By varying the device aspect ratio, the negative drag component is suppressed and a response consistent with pure momentum drag is recovered. In the momentum drag dominated regime, excellent quantitative agreement with the density and temperature dependence predicted for double bilayer graphene is found. PMID:27494491

  13. Negative Coulomb Drag in Double Bilayer Graphene.

    PubMed

    Li, J I A; Taniguchi, T; Watanabe, K; Hone, J; Levchenko, A; Dean, C R

    2016-07-22

    We report on an experimental measurement of Coulomb drag in a double quantum well structure consisting of bilayer-bilayer graphene, separated by few layer hexagonal boron nitride. At low temperatures and intermediate densities, a novel negative drag response with an inverse sign is observed, distinct from the momentum and energy drag mechanisms previously reported in double monolayer graphene. By varying the device aspect ratio, the negative drag component is suppressed and a response consistent with pure momentum drag is recovered. In the momentum drag dominated regime, excellent quantitative agreement with the density and temperature dependence predicted for double bilayer graphene is found.

  14. Negative Coulomb Drag in Double Bilayer Graphene

    NASA Astrophysics Data System (ADS)

    Li, J. I. A.; Taniguchi, T.; Watanabe, K.; Hone, J.; Levchenko, A.; Dean, C. R.

    2016-07-01

    We report on an experimental measurement of Coulomb drag in a double quantum well structure consisting of bilayer-bilayer graphene, separated by few layer hexagonal boron nitride. At low temperatures and intermediate densities, a novel negative drag response with an inverse sign is observed, distinct from the momentum and energy drag mechanisms previously reported in double monolayer graphene. By varying the device aspect ratio, the negative drag component is suppressed and a response consistent with pure momentum drag is recovered. In the momentum drag dominated regime, excellent quantitative agreement with the density and temperature dependence predicted for double bilayer graphene is found.

  15. Ionizing radiation and genetic risks. XVII. Formation mechanisms underlying naturally occurring DNA deletions in the human genome and their potential relevance for bridging the gap between induced DNA double-strand breaks and deletions in irradiated germ cells.

    PubMed

    Sankaranarayanan, Krishnaswami; Taleei, Reza; Rahmanian, Shirin; Nikjoo, Hooshang

    2013-01-01

    While much is known about radiation-induced DNA double-strand breaks (DSBs) and their repair, the question of how deletions of different sizes arise as a result of the processing of DSBs by the cell's repair systems has not been fully answered. In order to bridge this gap between DSBs and deletions, we critically reviewed published data on mechanisms pertaining to: (a) repair of DNA DSBs (from basic studies in this area); (b) formation of naturally occurring structural variation (SV) - especially of deletions - in the human genome (from genomic studies) and (c) radiation-induced mutations and structural chromosomal aberrations in mammalian somatic cells (from radiation mutagenesis and radiation cytogenetic studies). The specific aim was to assess the relative importance of the postulated mechanisms in generating deletions in the human genome and examine whether empirical data on radiation-induced deletions in mouse germ cells are consistent with predictions of these mechanisms. The mechanisms include (a) NHEJ, a DSB repair process that does not require any homology and which functions in all stages of the cell cycle (and is of particular relevance in G0/G1); (b) MMEJ, also a DSB repair process but which requires microhomology and which presumably functions in all cell cycle stages; (c) NAHR, a recombination-based DSB repair mechanism which operates in prophase I of meiosis in germ cells; (d) MMBIR, a microhomology-mediated, replication-based mechanism which operates in the S phase of the cell cycle, and (e) strand slippage during replication (involved in the origin of small insertions and deletions (INDELs). Our analysis permits the inference that, between them, these five mechanisms can explain nearly all naturally occurring deletions of different sizes identified in the human genome, NAHR and MMBIR being potentially more versatile in this regard. With respect to radiation-induced deletions, the basic studies suggest that those arising as a result of the operation

  16. Observing Double Stars

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.; Fulton, B. J.; Bianco, Federica B.; Martinez, John; Baxter, John; Brewer, Mark; Carro, Joseph; Collins, Sarah; Estrada, Chris; Johnson, Jolyon; Salam, Akash; Wallen, Vera; Warren, Naomi; Smith, Thomas C.; Armstrong, James D.; McGaughey, Steve; Pye, John; Mohanan, Kakkala; Church, Rebecca

    2012-05-01

    Double stars have been systematically observed since William Herschel initiated his program in 1779. In 1803 he reported that, to his surprise, many of the systems he had been observing for a quarter century were gravitationally bound binary stars. In 1830 the first binary orbital solution was obtained, leading eventually to the determination of stellar masses. Double star observations have been a prolific field, with observations and discoveries - often made by students and amateurs - routinely published in a number of specialized journals such as the Journal of Double Star Observations. All published double star observations from Herschel's to the present have been incorporated in the Washington Double Star Catalog. In addition to reviewing the history of visual double stars, we discuss four observational technologies and illustrate these with our own observational results from both California and Hawaii on telescopes ranging from small SCTs to the 2-meter Faulkes Telescope North on Haleakala. Two of these technologies are visual observations aimed primarily at published "hands-on" student science education, and CCD observations of both bright and very faint doubles. The other two are recent technologies that have launched a double star renaissance. These are lucky imaging and speckle interferometry, both of which can use electron-multiplying CCD cameras to allow short (30 ms or less) exposures that are read out at high speed with very low noise. Analysis of thousands of high speed exposures allows normal seeing limitations to be overcome so very close doubles can be accurately measured.

  17. 47 CFR 90.903 - Competitive bidding mechanisms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Bureau will establish and may vary the sequence in which 800 MHz SMR licenses for Spectrum Blocks A through V will be auctioned. (b) Grouping. (1) All EA licenses for Spectrum Blocks A through V will be... the auction, an alternative method of grouping these licenses for auction. (2) Spectrum blocks...

  18. Multidimensional period doubling structures.

    PubMed

    Lee, Jeong Yup; Flom, Dvir; Ben-Abraham, Shelomo I

    2016-05-01

    This paper develops the formalism necessary to generalize the period doubling sequence to arbitrary dimension by straightforward extension of the substitution and recursion rules. It is shown that the period doubling structures of arbitrary dimension are pure point diffractive. The symmetries of the structures are pointed out. PMID:27126116

  19. Silylene extrusion from organosilanes via double geminal Si-H bond activation by a Cp*Ru(kappa2-P,N)+ complex: observation of a key stoichiometric step in the glaser-tilley alkene hydrosilylation mechanism.

    PubMed

    Rankin, Matthew A; MacLean, Darren F; Schatte, Gabriele; McDonald, Robert; Stradiotto, Mark

    2007-12-26

    Treatment of Cp*RuCl(kappa2-P,N-2b) (2b = 2-NMe2-3-PiPr2-indene) with TlSO3CF3 produced the cyclometalated complex [4]+SO3CF3- in 94% isolated yield. Exposure of [4]+X- (X = B(C6F5)4 or SO3CF3) to Ph2SiH2 (10 equiv) or PhSiH3 afforded the corresponding [Cp*(mu-P,N-2b)(H)2Ru=SiRPh]+X- complexes, [5]+X- (R = Ph; X = B(C6F5)4, 82%; X = SO3CF3, 39%) and [6]+X- (R = H; X = B(C6F5)4, 94%; X = SO3CF3, 95%). Notably, these transformations represent the first documented examples of Ru-mediated silylene extrusion via double geminal Si-H bond activation of an organosilane-a key step in the recently proposed Glaser-Tilley (G-T) alkene hydrosilylation mechanism. Treatment of [5]+B(C6F5)4- with KN(SiMe3)2 or [6]+SO3CF3- with NaN(SiMe3)2 afforded the corresponding zwitterionic Cp*(mu-2-NMe2-3-PiPr2-indenide)(H)2Ru=SiRPh complex in 69% (R = Ph, 7) or 86% (R = H, 8) isolated yield. Both [6]+X- and 8 proved unreactive toward 1-hexene and styrene and provided negligible catalytic turnover in the attempted metal-mediated hydrosilylation of these substrates with PhSiH3, thereby providing further empirical evidence for the required intermediacy of base-free Ru=Si species in the G-T mechanism. Isomerization of the P,N-indene ligand backbone in [6]+X-, giving rise to [Cp*(mu-1-PiPr2-2-NMe2-indene)(H)2Ru=SiHPh]+X- ([9]+X-), was observed. In the case of [9]+SO3CF3-, net intramolecular addition of the Ru=Si-H group across the styrene-like C=C unit within the ligand backbone to give 10 (96% isolated yield) was observed. Crystallographic characterization data are provided for [4]+X-, [5]+X-, [6]+X-, 8, and 10.

  20. New insight on double-double radio galaxies

    NASA Astrophysics Data System (ADS)

    Nandi, Sumana

    2016-07-01

    Striking examples of episodic jet activity in active galactic nuclei (AGN) are the double-double radio galaxies (DDRGs) with two pairs of lobes emerging from the same central engine. The number of DDRGs reported so far is very limited, and it is important to identify more of these to provide a significant statistical overview of the conditions to trigger the jets and the role of jets in terms of feedback mechanisms that affect the host galaxies. Although most DDRGs were believed initially to be giant radio sources with sizes more than a Mpc, a significant number of smaller sized candidate DDRGs have also been identified in our recent study. We started GMRT observation of this sample to confirm that the sources are related to distinct epochs of nuclear activity. In addition to this radio observation we have also investigated the properties of the host galaxies and their environments to understand the triggering mechanisms for recurrent jet emission. Here, I will highlight the main results from these observations and discuss on the possible scenarios responsible for the episodic activity in different types of DDRGs .

  1. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  2. On fair, effective and efficient REDD mechanism design.

    PubMed

    Obersteiner, Michael; Huettner, Michael; Kraxner, Florian; McCallum, Ian; Aoki, Kentaro; Böttcher, Hannes; Fritz, Steffen; Gusti, Mykola; Havlik, Petr; Kindermann, Georg; Rametsteiner, Ewald; Reyers, Belinda

    2009-11-27

    The issues surrounding 'Reduced Emissions from Deforestation and Forest Degradation' (REDD) have become a major component of continuing negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). This paper aims to address two key requirements of any potential REDD mechanism: first, the generation of measurable, reportable and verifiable (MRV) REDD credits; and secondly, the sustainable and efficient provision of emission reductions under a robust financing regime.To ensure the supply of MRV credits, we advocate the establishment of an 'International Emission Reference Scenario Coordination Centre' (IERSCC). The IERSCC would act as a global clearing house for harmonized data to be used in implementing reference level methodologies. It would be tasked with the collection, reporting and subsequent processing of earth observation, deforestation- and degradation driver information in a globally consistent manner. The IERSCC would also assist, coordinate and supervise the computation of national reference scenarios according to rules negotiated under the UNFCCC. To overcome the threats of "market flooding" on the one hand and insufficient economic incentives for REDD on the other hand, we suggest an 'International Investment Reserve' (IIR) as REDD financing framework. In order to distribute the resources of the IIR we propose adopting an auctioning mechanism. Auctioning not only reveals the true emission reduction costs, but might also allow for incentivizing the protection of biodiversity and socio-economic values. The introduced concepts will be vital to ensure robustness, environmental integrity and economic efficiency of the future REDD mechanism.

  3. On fair, effective and efficient REDD mechanism design

    PubMed Central

    2009-01-01

    The issues surrounding 'Reduced Emissions from Deforestation and Forest Degradation' (REDD) have become a major component of continuing negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). This paper aims to address two key requirements of any potential REDD mechanism: first, the generation of measurable, reportable and verifiable (MRV) REDD credits; and secondly, the sustainable and efficient provision of emission reductions under a robust financing regime. To ensure the supply of MRV credits, we advocate the establishment of an 'International Emission Reference Scenario Coordination Centre' (IERSCC). The IERSCC would act as a global clearing house for harmonized data to be used in implementing reference level methodologies. It would be tasked with the collection, reporting and subsequent processing of earth observation, deforestation- and degradation driver information in a globally consistent manner. The IERSCC would also assist, coordinate and supervise the computation of national reference scenarios according to rules negotiated under the UNFCCC. To overcome the threats of "market flooding" on the one hand and insufficient economic incentives for REDD on the other hand, we suggest an 'International Investment Reserve' (IIR) as REDD financing framework. In order to distribute the resources of the IIR we propose adopting an auctioning mechanism. Auctioning not only reveals the true emission reduction costs, but might also allow for incentivizing the protection of biodiversity and socio-economic values. The introduced concepts will be vital to ensure robustness, environmental integrity and economic efficiency of the future REDD mechanism. PMID:19943927

  4. Comment on 'Biphoton double-slit experiment'

    SciTech Connect

    Oriols, X.

    2005-01-01

    In a recent paper [Phys. Rev. A 68, 033803 (2003)] experimental results on a double-slit configuration with two entangled bosons are presented. The authors argue that their data contradicts the de Broglie-Bohm interpretation of quantum mechanics. In this Comment we show that this conclusion is incorrect.

  5. Fluid dynamics of double diffusive systems

    SciTech Connect

    Koseff, J.R.

    1989-04-07

    A study of mixing processes in doubly diffusive systems is being conducted. Continuous gradients of two diffusing components (heat and salinity in our case) are being used as initial conditions, and forcing is introduced by lateral heating and surface shear. The goals of the proposed work include: (1) quantification of the effects of finite amplitude disturbances on stable, double diffusive systems, particularly with respect to lateral heating, (2) development of an improved understanding of the physical phenomena present in wind-driven shear flows in double diffusive stratified environments, (3) increasing our knowledge-base on turbulent flow in stratified environments and how to represent it, and (4) formulation of a numerical code for such flows. The work is being carried out in an experimental facility which is located in the Stanford Environmental Fluid Mechanics Laboratory, and on laboratory minicomputers and CRAY computers. In particular we are focusing on the following key issues: (1) the formation and propagation of double diffusive intrusions away from a heated wall and the effects of lateral heating on the double diffusive system; (2) the interaction between the double diffusively influenced fluxes and the turbulence induced fluxes; (3) the measurement of heat and mass fluxes; and (4) the influence of double diffusive gradients on mixed layer deepening. 1 fig.

  6. Dynamics of Double Stochastic Operators

    NASA Astrophysics Data System (ADS)

    Saburov, Mansoor

    2016-03-01

    A double stochastic operator is a generalization of a double stochastic matrix. In this paper, we study the dynamics of double stochastic operators. We give a criterion for a regularity of a double stochastic operator in terms of absences of its periodic points. We provide some examples to insure that, in general, a trajectory of a double stochastic operator may converge to any interior point of the simplex.

  7. Double Helical Fluid Containment

    NASA Astrophysics Data System (ADS)

    Lowry, Brian

    2003-11-01

    In the absence of gravity or at micro-scales, helical wires can support cylindrical volumes of fluid of infinite length, making them convenient as conduits. However, fixed contact line double helical fluid volumes have the additional property that they can be drained to zero volume without loss of stability to constant pressure disturbances. Thus the two-wire support is a convenient microgravity or micro-scale container as well as conduit. For evenly spaced wires, continuous draining of a cylindrical volume to zero is possible for double helices ranging from moderate pitch to the parallel wire case. Double helices of steeper pitch are stable as cylinders and at zero volume, but are unstable for some range of intermediate volumes. This unstable zone is very strongly dependent on the offset between the helical wires, varying rapidly for offsets other than 180 degrees. Preliminary experimental results validate the theoretical predictions.

  8. Double face sealing device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (Inventor)

    1991-01-01

    A double face sealing device for mounting between two surfaces to provide an airtight and fluid-tight seal between a closure member bearing one of the surfaces and a structure or housing bearing the other surface which extends around the opening or hatchway to be closed. The double face sealing device includes a plurality of sections or segments mounted to one of the surfaces, each having a main body portion, a pair of outwardly extending and diverging, cantilever, spring arms, and a pair of inwardly extending and diverging, cantilever, spring arms, an elastomeric cover on the distal, free, ends of the outwardly extending and diverging spring arms, and an elastomeric cover on the distal, free, ends of the inwardly extending and diverging spring arms. The double face sealing device has application or use in all environments requiring a seal, but is particularly useful to seal openings or hatchways between compartments of spacecraft or aircraft.

  9. Double Emulsion Templated Celloidosomes

    NASA Astrophysics Data System (ADS)

    Arriaga, Laura R.; Marquez, Samantha M.; Kim, Shin-Hyun; Chang, Connie; Wilking, Jim; Monroy, Francisco; Marquez, Manuel; Weitz, David A.

    2012-02-01

    We present a novel approach for fabricating celloidosomes, which represent a hollow and spherical three-dimensional self-assembly of living cells encapsulating an aqueous core. Glass- capillary microfluidics is used to generate monodisperse water-in-oil-in-water double emulsion templates using lipids as stabilizers. Such templates allow for obtaining single but also double concentric celloidosomes. In addition, after a solvent removal step the double emulsion templates turn into monodisperse lipid vesicles, whose membrane spontaneously phase separates when choosing the adequate lipid composition, providing the adequate scaffold for fabricating Janus-celloidosomes. These structures may find applications in the development of bioreactors in which the synergistic effects of two different types of cells selectively adsorbed on one of the vesicle hemispheres may be exploited.

  10. Revisting the Double Helix

    SciTech Connect

    Ha, Taekjip

    2010-12-08

    Properties of DNA double helix have been studied for over 60 years. Yet as more sensitive tools become available, fundamental assumptions in our understanding of these properties are being challenged. One such question is over the flexibility of DNA. Looping or bending of DNA on short length scales is essential for many cellular processes but it is highly controversial exactly how flexible the DNA is. Using a new, single-molecule based method, we found that DNA of lengths as short as 50 base pairs can form a circle more than 108 times faster than theoretical predictions. Another question concerns the physical principles governing the reversible, helix-coil transitions of DNA between the double helix and single strands. Using porous nanocontainers, we found that the rate of double helix formation shows an abrupt 100 fold change depending on whether there are 7 or more contiguous base pairs or not.

  11. Tracking The Double Eagle

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Last summer a trio of aeronauts made aviation history. Ben Abruzzo, Maxie Anderson and Larry Newman, all of Albuquerque, New Mexico, piloted their balloon Double Eagle I1 from Presque Isle, Maine to Miserey, France, some 50 miles from Paris. They were the first to negotiate a successful Atlantic crossing in a freeflying balloon after a score of attempts over a span of more than a century. A year earlier, Abruzzo and Anderson had made an unsuccessful try in their predecessor balloon Double Eagle. On that occasion, a NASA-developed satellite beacon helped save their lives. Carried aboard the balloon, the simple, seven-pound beacon continuously transmitted signals to NASA's Nimbus-6 satellite. Nimbus relayed the signals to monitors at Goddard Space Flight Center, enabling Goddard to compute the balloon's position. Position reports were then telephoned regularly to Double Eagle's control center at Bedford, Massachusetts. This monitoring system proved invaluable when the balloon encountered trouble several days after liftoff.

  12. Design friendly double patterning

    NASA Astrophysics Data System (ADS)

    Yesilada, Emek

    2012-03-01

    Double patterning using 193nm immersion has been adapted as the solution to enable 2x nm technology nodes until the arrival of EUV tools. As a result the past few years have seen a huge effort in creating double patterning friendly design flows. These flows have so far proposed a combination of decomposition rules at cell level and/or at placement level as well as sophisticated decomposition tools with varying density, design iteration and decomposition complexity penalties. What is more, designers have to familiarize themselves with double patterning challenges and decomposition tools. In this paper an alternative approach is presented that allows the development of dense standard cells with minimal impact on design flow due to double patterning. A real case study is done on 20nm node first metal layer where standard cells are designed without considering decomposition restrictions. The resulting layout is carefully studied in order to establish decomposition or color rules that can map the layout into two masks required for double patterning but without the need of complex coloring algorithms. Since the rules are derived from a decomposition unaware design they do not in return impose heavy restrictions on the design at the cell or placement level and show substantial density gains compared to previously proposed methods. Other key advantages are a simplified design flow without complex decomposition tools that can generate a faster time to market solution all at the same time keeping designers isolated from the challenges of the double patterning. The derived design rules highlight process development path required for design driven manufacturing.

  13. Double checking: a second look

    PubMed Central

    Chreim, Samia; Forster, Alan

    2015-01-01

    Abstract Rationale, aims and objectives Double checking is a standard practice in many areas of health care, notwithstanding the lack of evidence supporting its efficacy. We ask in this study: ‘How do front line practitioners conceptualize double checking? What are the weaknesses of double checking? What alternate views of double checking could render it a more robust process?’ Method This is part of a larger qualitative study based on 85 semi‐structured interviews of health care practitioners in general internal medicine and obstetrics and neonatology; thematic analysis of the transcribed interviews was undertaken. Inductive and deductive themes are reported. Results Weaknesses in the double checking process include inconsistent conceptualization of double checking, double (or more) checking as a costly and time‐consuming procedure, double checking trusted as an accepted and stand‐alone process, and double checking as preventing reporting of near misses. Alternate views of double checking that would render it a more robust process include recognizing that double checking requires training and a dedicated environment, Introducing automated double checking, and expanding double checking beyond error detection. These results are linked with the concepts of collective efficiency thoroughness trade off (ETTO), an in‐family approach, and resilience. Conclusion(s) Double checking deserves more questioning, as there are limitations to the process. Practitioners could view double checking through alternate lenses, and thus help strengthen this ubiquitous practice that is rarely challenged. PMID:26568537

  14. Double Bragg Interferometry.

    PubMed

    Ahlers, H; Müntinga, H; Wenzlawski, A; Krutzik, M; Tackmann, G; Abend, S; Gaaloul, N; Giese, E; Roura, A; Kuhl, R; Lämmerzahl, C; Peters, A; Windpassinger, P; Sengstock, K; Schleich, W P; Ertmer, W; Rasel, E M

    2016-04-29

    We employ light-induced double Bragg diffraction of delta-kick collimated Bose-Einstein condensates to create three symmetric Mach-Zehnder interferometers. They rely on (i) first-order, (ii) two successive first-order, and (iii) second-order processes which demonstrate the scalability of the corresponding momentum transfer. With respect to devices based on conventional Bragg scattering, these symmetric interferometers double the scale factor and feature a better suppression of noise and systematic uncertainties intrinsic to the diffraction process. Moreover, we utilize these interferometers as tiltmeters for monitoring their inclination with respect to gravity. PMID:27176520

  15. Double arch mirror study

    NASA Technical Reports Server (NTRS)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  16. ? - ? Double twinning in magnesium

    NASA Astrophysics Data System (ADS)

    Jäger, Aleš; Ostapovets, Andriy; Molnár, Peter; Lejček, Pavel

    2011-08-01

    It is demonstrated that metalworking processes performed at different temperatures can lead to the ? - ? double twinning. This twinning mode has been observed during direct extrusion of the coarse-grained Mg-0.3at.%Al alloy at 433 K and analysed in detail on room-temperature rolled magnesium single crystal with the c-axis parallel to transverse direction and the a-axis parallel to rolling direction. The ? - ? double twins originated during initial stage of the formation on coarse-grained and single-crystalline structure.

  17. Double Photoionization Near Threshold

    NASA Technical Reports Server (NTRS)

    Wehlitz, Ralf

    2007-01-01

    The threshold region of the double-photoionization cross section is of particular interest because both ejected electrons move slowly in the Coulomb field of the residual ion. Near threshold both electrons have time to interact with each other and with the residual ion. Also, different theoretical models compete to describe the double-photoionization cross section in the threshold region. We have investigated that cross section for lithium and beryllium and have analyzed our data with respect to the latest results in the Coulomb-dipole theory. We find that our data support the idea of a Coulomb-dipole interaction.

  18. A simple pharmacokinetics subroutine for modeling double peak phenomenon.

    PubMed

    Mirfazaelian, Ahmad; Mahmoudian, Massoud

    2006-04-01

    Double peak absorption has been described with several orally administered drugs. Numerous reasons have been implicated in causing the double peak. DRUG-KNT--a pharmacokinetic software developed previously for fitting one and two compartment kinetics using the iterative curve stripping method--was modified and a revised subroutine was incorporated to solve double-peak models. This subroutine considers the double peak as two hypothetical doses administered with a time gap. The fitting capability of the presented model was verified using four sets of data showing double peak profiles extracted from the literature (piroxicam, ranitidine, phenazopyridine and talinolol). Visual inspection and statistical diagnostics showed that the present algorithm provided adequate curve fit disregarding the mechanism involved in the emergence of the secondary peaks. Statistical diagnostic parameters (RSS, AIC and R2) generally showed good fitness in the plasma profile prediction by this model. It was concluded that the algorithm presented herein provides adequate predicted curves in cases of the double peak phenomenon.

  19. Comparing the 2000 and 2005 factors affecting the selling price of feeder cattle sold at Arkansas livestock auctions.

    PubMed

    Troxel, T R; Barham, B L

    2007-12-01

    The objectives of the study were to determine how factors affecting the selling price of feeder calves changed from 2000 to 2005 and to examine the perception that discounts narrow or even disappear as calf supplies decrease and selling prices increase. Data from weekly Arkansas livestock auctions were collected from January 1 to December 31 in 2000 and 2005. Data included calf sex, breed type, color, muscle score, horn status, frame score, fill, condition, health, and BW. Mean selling prices for 2000 and 2005 were $92.91 +/- 15.05 and $118.32 +/- 15.13 (mean +/- SD; $/45.45 kg), respectively. Individual price observations were subtracted from the respective annual means and became the dependent variable. The selling prices for feeder calves sold in groups of 2 to 5 calves and in groups of >/= 6 calves were greater in 2005 than 2000 (P < 0.001). Steers received a greater premium ($6.48 +/- 0.09 vs. $6.02 +/- 0.08; mean +/- SE) and bull calves received greater discounts ($0.30 +/- 0.14 vs. $1.68 +/- 0.09) in 2005 than in 2000. Breeds types that increased in value from 2000 to 2005 were Angus x Hereford, Angus, Angus x Charolais, and Brahman (P < 0.001). Breed types that received a reduced selling price in 2005 compared with 2000 (P < 0.001) were one-fourth Brahman Cross, Charolais, Charolais x Limousin, Hereford x Limousin, Limousin, Limousin x one-fourth Brahman, Longhorn, Saler and Simmental. Yellow-white face, black-white face, black, and gray feeder calves received an increase in selling price from 2000 to 2005 (P < 0.001). Although fewer horned feeder calves were sold in 2005 (P < 0.01), they received greater discounts in 2005 than 2000 (-$2.86 +/- 0.16 and -$0.51 +/- 0.09; P < 0.001). In 2005, large-framed feeder calves did not receive the premium detected in 2000, but medium-framed feeder calves in 2005 received a greater selling price compared with 2000. Feeder calves with a muscle score of 1 received a greater premium in 2005 compared with 2000 ($2.58 +/- 0

  20. Comparing the 2000 and 2005 factors affecting the selling price of feeder cattle sold at Arkansas livestock auctions.

    PubMed

    Troxel, T R; Barham, B L

    2007-12-01

    The objectives of the study were to determine how factors affecting the selling price of feeder calves changed from 2000 to 2005 and to examine the perception that discounts narrow or even disappear as calf supplies decrease and selling prices increase. Data from weekly Arkansas livestock auctions were collected from January 1 to December 31 in 2000 and 2005. Data included calf sex, breed type, color, muscle score, horn status, frame score, fill, condition, health, and BW. Mean selling prices for 2000 and 2005 were $92.91 +/- 15.05 and $118.32 +/- 15.13 (mean +/- SD; $/45.45 kg), respectively. Individual price observations were subtracted from the respective annual means and became the dependent variable. The selling prices for feeder calves sold in groups of 2 to 5 calves and in groups of >/= 6 calves were greater in 2005 than 2000 (P < 0.001). Steers received a greater premium ($6.48 +/- 0.09 vs. $6.02 +/- 0.08; mean +/- SE) and bull calves received greater discounts ($0.30 +/- 0.14 vs. $1.68 +/- 0.09) in 2005 than in 2000. Breeds types that increased in value from 2000 to 2005 were Angus x Hereford, Angus, Angus x Charolais, and Brahman (P < 0.001). Breed types that received a reduced selling price in 2005 compared with 2000 (P < 0.001) were one-fourth Brahman Cross, Charolais, Charolais x Limousin, Hereford x Limousin, Limousin, Limousin x one-fourth Brahman, Longhorn, Saler and Simmental. Yellow-white face, black-white face, black, and gray feeder calves received an increase in selling price from 2000 to 2005 (P < 0.001). Although fewer horned feeder calves were sold in 2005 (P < 0.01), they received greater discounts in 2005 than 2000 (-$2.86 +/- 0.16 and -$0.51 +/- 0.09; P < 0.001). In 2005, large-framed feeder calves did not receive the premium detected in 2000, but medium-framed feeder calves in 2005 received a greater selling price compared with 2000. Feeder calves with a muscle score of 1 received a greater premium in 2005 compared with 2000 ($2.58 +/- 0