Agent Competition Research Articles

Régimen político y límites de la democracia en regiones afectadas por conflicto armado y cultivos ilícitos: el caso del Catatumbo

This article is based on research carried out in three municipalities of the Catatumbo (North Santander department, Colombia) region, and analyzes institutional arrangement dysfunctions that arise from active illegal armed groups and illicit crops, pointing out the effects on the political regime and the exercise of democracy and stating the problems that must be faced by local governments in order to perform their mandate. The article suggests that Government action in this region has been affected by deep failures in legitimacy, efficiency, and effectiveness, which generated critical limitations to governability in that territory. Such failures are related to the factual suppression of the social contract and to the ineffectiveness of a democracy in its least representation. It concludes that in the municipalities under examination, Government failures strongly reduce the settlement costs for illegal armed groups to access territory control and to establish as protection agents in competition with the State. They also lead towards the establishment of a vicious affectation cycle where the cost increase of the public investment required to correct such failures in turn reduces political actors’ interest in solving them, thus creating a chronic trap that reduces governability in the regional level.

A scintillation proximity assay for dengue virus NS5 2′- O-methyltransferase—kinetic and inhibition analyses

Dengue virus (DENV) NS5 possesses methyltransferase (MTase) activity at its N-terminal amino acid sequence and is responsible for formation of a type 1 cap structure, m 7GpppAm 2′- O in the viral genomic RNA. Optimal in vitro conditions for DENV2 2′- O-MTase activity were characterized using purified recombinant protein and a short biotinylated GTP-capped RNA template. Steady-state kinetics parameters derived from initial velocities were used to establish a robust scintillation proximity assay for compound testing. Pre-incubation studies showed that MTase–AdoMet and MTase–RNA complexes were equally catalytically competent and the enzyme supports a random bi bi kinetic mechanism. The assay was validated with competitive inhibitory agents, S-adenosyl-homocysteine and two homologues, sinefungin and dehydrosinefungin. A GTP-binding pocket present at the N-terminal of DENV2 MTase was previously postulated to be the cap-binding site. Interestingly, inhibition of the enzyme by GTP was two-fold lower than with RNA cap analogues, G[5′]ppp[5′]A and m 7G[5′]ppp[5′]A and about three-fold poorer than a two-way methylated analogue, m 7G[5′]ppp[5′]m 7G. This assay allows rapid and highly sensitive detection of 2′- O-MTase activity and can be readily adapted for high-throughput screening for inhibitory compounds. It is suitable for determination of enzymatic activities of a wide variety of RNA capping MTases.

Recombinant Bacillus subtilis expressing the Clostridium perfringens alpha toxoid is a candidate orally delivered vaccine against necrotic enteritis.

Recombinant Bacillus subtilis endospores have been used to vaccinate against tetanus and anthrax. In this work, we have developed spores that could be used to vaccinate against Clostridium perfringens alpha toxin and that could be used to protect against gas gangrene in humans and necrotic enteritis in poultry. The primary active agent in both cases is alpha toxin. A carboxy-terminal segment of the alpha toxin gene (cpa) fused to the glutathione-S-transferase (GST) gene was cloned in B. subtilis such that the encoded GST-Cpa(247-370) polypeptide had been expressed in the following three different ways: expression in the vegetative cell, expression on the surface of the spore coat (fused to the CotB spore coat protein), and a combined approach of spore coat expression coupled with expression in the vegetative cell. Mice immunized orally or nasally with three doses of recombinant spores that carried GST-Cpa(247-370) on the spore surface showed the most striking responses. This included seroconversion with anti-Cpa(247-370)-specific immunoglobulin G (IgG) responses in their sera, a Th2 bias, and secretory IgA responses in saliva, feces, and lung samples. Neutralizing IgG antibodies to alpha toxin were detected using in vitro and in vivo assays, and a toxin challenge established protection. Mice immunized nasally or orally with recombinant spores were protected against a challenge with 12 median lethal doses of alpha toxin. Existing use of spores as competitive exclusion agents in animal feeds supports their use as a potentially economical and heat-stable vaccine for the poultry industry.

A Procedure for High-Yield Spore Production by Bacillus s ubtilis

Bacillus subtilis spores have a number of potential applications, which include their use as probiotics and competitive exclusion agents to control zoonotic pathogens in animal production. The effect of cultivation conditions on Bacillus subtilis growth and sporulation was investigated in batch bioreactions performed at a 2-L scale. Studies of the cultivation conditions (pH, dissolved oxygen concentration, and media composition) led to an increase of the maximum concentration of vegetative cell from 2.6 x 10(9) to 2.2 x 10(10) cells mL(-)(1) and the spore concentration from 4.2 x 10(8) to 5.6 x 10(9) spores mL(-)(1). A fed-batch bioprocess was developed with the addition of a nutrient feeding solution using an exponential feeding profile obtained from the mass balance equations. Using the developed feeding profile, starting at the middle of the exponential growth phase and finishing in the late exponential phase, an increase of the maximum vegetative cell concentration and spore concentration up to 3.6 x 10(10) cells mL(-)(1) and 7.4 x 10(9) spores mL(-)(1), respectively, was obtained. Using the developed fed-batch bioreaction a 14-fold increase in the concentration of the vegetative cells was achieved. Moreover, the efficiency of sporulation under fed-batch bioreaction was 21%, which permitted a 19-fold increase in the final spore concentration, to a final value of 7.4 x 10(9) spores mL(-)(1). This represents a 3-fold increase relative to the highest reported value for Bacillus subtilis spore production.

On the Competition of Asymmetric Agents

Abstract Rank-order tournaments are usually implemented in organizations to provide incentives for eliciting employees’ effort and/or to identify the agent with the higher ability, for example in promotion tournaments. We close a gap in the literature by experimentally analyzing a ceteris paribus variation of the prize spread - being the major design feature of tournaments - in a symmetric and an asymmetric setting. We find that effort significantly increases with the prize spread as predicted by standard theory. However, only for sufficiently large prize spreads weak players competing against strong players strain themselves all the more and sorting of agents is feasible.

Enquête de pratique sur l’utilisation en France des curares chez l’adulte en anesthésie

Guidelines about the use of neuromuscular blocking agents based on a national consensus conference have been published in 2000. A survey was carried out to assess adherence to these guidelines. An online questionnaire was designed from the different guidelines concerning the use of muscle relaxant for tracheal intubation and surgery, monitoring and antagonism of neuromuscular blockade. In addition, question about the knowledge of the pharmacodynamics of neuromuscular blocking agents were asked. Analysis concerned 1230 answers from senior anaesthetists. Tracheal intubation is facilitated by the use of a competitive agent or by succinylcholine by 58 and 8% of responders respectively. Atracurium and cisatracurium were most frequently used (49 and 44%, respectively). The duration of effect of an intubating dose of atracurium, vecuronium or rocuronium was estimated equal or below 60 min by more than half of responders, whereas that of cisatracurium was longer. Fifty-two or 74% of responders used neuromuscular monitoring, whether a single or repeated dose of muscle relaxant was administered. Antagonism of neuromuscular blockade was systematic, frequent, and episodic or excluded by 6, 26, 55 and 13% of responders, respectively. Monitoring and antagonism of neuromuscular blockade are underused despite the guidelines. Underestimation of the risk of postoperative residual curarization is linked to the underestimation of the duration of competitive neuromuscular blocking agents.

Dehydrocyclization of Diphenylamine to Carbazole Over Platinum Catalysts

The gas-phase dehydrocyclization of diphenylamine (DPA) to carbazole over alumina-supported 0.4 wt.% Pt catalysts in a fix-bed reactor has been studied. The reaction was carried out at a temperature of 550 °C in the presence of hydrogen. All catalysts became well dispersed Pt after in situ reduction. Pt catalysts prepared in the presence of a competitive adsorbate (citric acid) were reasonably active during first hours on stream (DPA conversion higher than 90%). However, later, their activity decreased rapidly, except the catalyst prepared in the presence of a higher concentration of the competitive agent. The same trend was observed for the Pt catalyst prepared by wet impregnation. The activity of the catalysts prepared by a microemulsion technique was very high and stable during testing, the conversion of DPA being higher than 93%. However, the selectivities of catalysts prepared in the presence of citric acid gradually decreased with time on stream (TOS). The initial selectivityof such prepared catalysts for carbazole was about 60%. The same trend was observed for catalysts prepared by microemulsion technique. The highest selectivities, 73%, were obtained over the catalysts prepared by wet impregnation; it dropped after 6 days of testing to about 62%.

Towards heterogeneous robot teams for disaster mitigation: Results and performance metrics from RoboCup rescue

AbstractUrban Search and Rescue is a growing area of robotic research. The RoboCup Federation has recognized this, and has created the new Virtual Robots competition to complement its existing physical robot and agent competitions. In order to successfully compete in this competition, teams need to field multi‐robot solutions that cooperatively explore and map an environment while searching for victims. This paper presents the results of the first annual RoboCup Rescue Virtual competition. It provides details on the metrics used to judge the contestants as well as summaries of the algorithms used by the top four teams. This allows readers to compare and contrast these effective approaches. Furthermore, the simulation engine itself is examined and real‐world validation results on the engine and algorithms are offered. © 2007 Wiley Periodicals, Inc.

Epipolar geometry estimation based on evolutionary agents

This paper presents a novel approach based on the use of evolutionary agents for epipolar geometry estimation. In contrast to conventional nonlinear optimization methods, the proposed technique employs each agent to denote a minimal subset to compute the fundamental matrix, and considers the data set of correspondences as a 1D cellular environment, in which the agents inhabit and evolve. The agents execute some evolutionary behavior, and evolve autonomously in a vast solution space to reach the optimal (or near optima) result. Then three different techniques are proposed in order to improve the searching ability and computational efficiency of the original agents. Subset template enables agents to collaborate more efficiently with each other, and inherit accurate information from the whole agent set. Competitive evolutionary agent (CEA) and finite multiple evolutionary agent (FMEA) apply a better evolutionary strategy or decision rule, and focus on different aspects of the evolutionary process. Experimental results with both synthetic data and real images show that the proposed agent-based approaches perform better than other typical methods in terms of accuracy and speed, and are more robust to noise and outliers.

Competitive agents in a market: Statistical physics of the minority game

A brief review is presented of the minority game, a simple frustrated many-body system stimulated by considerations of a market of competitive speculative agents. Its cooperative behaviour exhibits phase transitions and both ergodic and non-ergodic regimes. It provides novel challenges to statistical physics, reminiscent of those of mean-field spin glasses.

P1763 Bacillus smithii TBMI12 spores as a potential competitive exclusion agent against Salmonella enteritidis

P1763 Bacillus smithii TBMI12 spores as a potential competitive exclusion agent against Salmonella enteritidis

Comparison of alpha1-adrenergic receptor cell-membrane stationary phases prepared from expressed cell line and from rabbit hepatocytes

A G-protein-coupled receptor-cell-membrane stationary phase (CMSP) has been prepared by immobilizing cell membranes on the surface of silica, as carrier. The resulting HEK293 alpha1A adrenoceptor cell-membrane stationary phase can be used for rapid on-line chromatographic determination of potential subtype-selective alpha1-adrenoceptor ligand-binding affinities for alpha 1-adrenoceptor subtypes. The objective of the research was to study whether cell lines stably overexpressing subtype receptors could improve the sensitivity and specificity of cell-membrane chromatography (CMC) compared with use of homogenized tissue and cells in primary culture. Effects of mobile-phase ionic strength, sample concentration, and the presence of competitive agents on ligand-receptor interaction in CMSP were also evaluated. We found that cell lines stably overexpressing subtype receptors led to improved sensitivity and specificity in CMC. The technique leads to useful procedures-cell-membrane stationary phases may, for example, facilitate exploration of ligand-receptor interaction and determination of ligand-receptor binding affinity in initial screening and separation of lead compounds or active components in Chinese traditional natural medicine and herbs. This might eventually be an important contribution and an addition to our collection of techniques.

Determination of the Binding Constant of Terbium-Transferrin

Apotransferrin (apo Tf) in 0.1 M N-(2hydroxyethyl)piperazine-N2-ethanesulfanic acid at 25 ˚C and pH 7.4 has been titrated with acidic solution of Tb3+. The binding of Tb3+ at the two specific metal-binding sites of transferrin was followed from the changes in the difference UV spectra at 245 nm. The molar absorptivity per binding site for Tb3+-Tf is 22,500 ± 1000 M-1cm-1. To determine the Tb-Tf binding constants, apo Tf was titrated with Tb3+ solutions which also contained nitrilotriacetic acid as a competitive chelating agent. The sequential macroscopic equilibrium constants for the binding of two metal ions are log K1 = 9.96 ± 0.38 and log K2 = 6.37± 0.38. Titrations of both C-terminal and N-terminal monoferric transferrin with Tb3+ indicate that terbium binding is stronger at the C-terminal binding site. The value of K1 for Tb3+ is substantially higher than the teransferrin binding constants reported for larger lanthanides. It is possible that there are steric interferences to the binding of larger lanthanides. However, an analysis of the transferrin binding constants using linear free energy relationships for metal complexation suggests that the metal ionic radius alone is not the major determining factor. A change in the number of coordinated water molecules in the aqueous ions for Tb3+ compared to the larger lanthanides may be a more important factor.

Learning enabled cooperative agent behavior in an evolutionary and competitive environment

The proposed method is implemented in three steps: first, when a variation in environment is perceived, agents take appropriate actions. Second, the behaviors are stimulated and controlled through communication with other agents. Finally, the most frequently stimulated behavior is adopted as a group behavior strategy. In this paper, two different reward models, reward model 1 and reward model 2, are applied. Each reward model is designed to consider the reinforcement or constraint of behaviors. In competitive agent environments, the behavior considered to be advantageous is reinforced as adding reward values. On the contrary, the behavior considered to be disadvantageous is constrained by reducing the reward values. The validity of this strategy is verified through simulation.

Agent Composition via Role-based Infrastructures

Software agents represent an interesting paradigm to approach complex and distributed systems. Their sociality enables to build multiagent systems, where different agents interact to pursue their goals. Multiagent systems can involve both cooperative and competitive agents. In both cases, the composition of different agents is an issue that must be faced by developers. In this paper, we propose to build infrastructures based on roles, which are abstractions that enable the composition of different agents in an open scenario. Some concrete examples are provided to support our proposal.

Mapping of FVIII inhibitor epitopes using cellulose-bound synthetic peptide arrays

Epitope mapping using antibodies against factor VIII (FVIII) has been performed using blotting techniques with truncated and/or digested FVIII molecules. Here, we focused on the precise mapping of affinity purified IgG from patients with an immune response against blood clotting FVIII using synthetic peptide arrays on cellulose membranes comprising the entire sequence of FVIII. The aim was to elucidate the epitope profile from different inhibitors and possibly detect new epitopes, which have not been described before. The epitope patterns from five patients showed reactivity with all domains in the FVIII molecule, but were different between various patients. These results included epitopes usually buried within the folded protein. However, in competition assays using FVIII as competitive agent in a mixture with inhibitor IgG, the most immunogenic regions were located in the FVIII light chain. Our results show that the C1 domain was the region with highest immunogenicity in all patients. Here, we demonstrate that the SPOT method is very well suited for the precise location of epitopes in the core of the protein, which usually cannot be detected by other methods.

The design of an agent for modelling supply chain network dynamics

A useful insight into managerial decision making can be found from simulation of business systems, but existing work on simulation of supply chain behaviour has largely considered non-competitive chains. Where competitive agents have been examined, they have generally had a simple structure and been used for fundamental examination of stability and equilibria rather than providing practical guidance to managers. In this paper, a new agent for the study of competitive supply chain network dynamics is proposed. The novel features of the agent include the ability to select between competing vendors, distribute orders preferentially among many customers, manage production and inventory, and determine price based on competitive behaviour. The structure of the agent is related to existing business models and sufficient details are provided to allow implementation. The agent is tested to demonstrate that it recreates the main results of the existing modelling and management literature on supply chain dynamics. A brief exploration of competitive dynamics is given to confirm that the proposed agent can respond to competition. The results demonstrate that overall profitability for a supply chain network is maximised when businesses operate collectively. It is possible for an individual business to achieve higher profits by adopting a more competitive stance, but the consequence of this is that the overall profitability of the network is reduced. The agent will be of use for a broad range of studies on the long-run effect of management decisions on their network of suppliers and customers.

Gobernanza de las nanotecnologías

Nanotechnologies and the Converging Technologies Programmes (CT) put forward relevant challenges to the governance of science and technology, because their development takes place in the context of a transnational R+D+i system with a plurality of competitive and cooperative agents who pursue a diversity of goals. How to integrate the plurality of technoscientific agencies and how to establish the research priorities of CT Programmes constitute significant problems. This paper presents a comparison between the American (NBIC) and European (CTEKS) CT programmes in order to analyse their commonalities and differences. It is argued that nanosciences and nanotechnologies constitute one of the main instances of contemporary technoscience, assuming the thesis that in technoscience (contrary to what happens in traditional science), scientific knowledge is not and end in itself, but just an instrument to obtain social, political, economic or military ends. Then, it is proposed a general philosophical hypotesis about the colonization and industrialization of the nanocosmos, and the notion of scientific agenda is put forward in order to analyse and characterise the diverse models of governance.

Self-Regulation and Government Oversight

Self-regulation is a feature of a number of professions. For example, in the U.S. the government delegates aspects of financial market regulation to self-regulatory organizations (SROs) like the New York Stock Exchange and the National Association of Securities Dealers. We analyse one regulatory task of an SRO, enforcing antifraud rules so agents will not cheat customers. Specifically, we model contracting/enforcement as a two-tier problem. An SRO chooses its enforcement policy: the likelihood that an agent is investigated for fraud and a penalty schedule. Given an enforcement policy, agents compete by offering contracts that maximize customers' expected utility. We assume that the SRO's objective is to maximize the welfare of its members, the agents. We show that the SRO chooses a more lax enforcement policy—meaning less frequent investigations—than what customers would choose. A general conclusion is that control of the enforcement policy governing contracts confers substantial market power to a group of otherwise competitive agents. We also investigate government oversight of the self-regulatory process. The threat of government enforcement leads to more enforcement by the SRO, just enough to pre-empt any government enforcement. Copyright 2005, Wiley-Blackwell.

Bi-level Dynamic Optimization of Pumped-storage Hydroplants in a Competitive Power Pool. Part II: Case Studies

This paper is the second in a series of two articles. It presents the results obtained through numerical simulation with the bi-level dynamic optimization model develop to program the daily operation of a pumped-storage hydroplant in a competitive Electricity Market with a centralized structure. In the scenario proposed for the demand and valuation of water in the upper reservoir, the model of perfect competition and the model of Cournot achieve in practice the same fuel economy so there are no differences from the point of view of the competitive pool operator. From the point of view of the competitive pool agent, the pumped-storage hydroplant, the situation is completely different as regards the apportion of benefits resulting from each model, being the model of perfect competition more advantageous.