73,821 research outputs found

    Professional Hockey Elements Attracting Fans to AHL Games

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    The purpose of this study was to determine the relationships between on-ice professional hockey elements and attendance at American Hockey League games. It was important to this study that the AHL was the most successful North American professional hockey league in recent years in terms of increasing attendance and in 2015-16 the league set a record for total fans attending games at around 7 million. Also, recently the NHL and consequently AHL have implemented rules to increase scoring and decrease fighting; therefore it was important to conclude if those changes resulted in changed fan motivation to attend games. It was previously known that AHL fans preferred high scoring and high fighting games and were indifferent about team success when deciding on attending games before the rule changes. Data were collected on average goals per game, average fights per game, divisional rivalry games, winning percentage, and percent capacity filled for each of the 30 AHL teams’ weekend games in the 2015-16 season. A regression was used to discover the relationships between the variables and attendance. It was concluded that average goals per game and average fights per game had a significant relationship with attendance, while team success had a not significant relationship with attendance. Even after the many rule changes to increase scoring and decrease fighting, fans still preferred to go to games that were high scoring and high fighting. This was important for AHL business executives to know because they were changing rules to decrease fighting, yet fans preferred high fighting. Rule changes made should have been to the fans liking so the league as a business could have profit maximized, therefore this information can help them make better decisions moving forward

    Quorum-quenching activity of the AHL-lactonase from <i>Bacillus licheniformis</i> DAHB1 inhibits vibrio biofilm formation in vitro and reduces shrimp intestinal colonisation and mortality

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    Vibrio parahaemolyticus is a significant cause of gastroenteritis resulting from the consumption of undercooked sea foods and often cause significant infections in shrimp aquaculture. Vibrio virulence is associated with biofilm formation and is regulated by N-acylated homoserine lactone (AHL)-mediated quorum sensing. In an attempt to reduce vibrio colonisation of shrimps and mortality, we screened native intestinal bacilli from Indian white shrimps (Fenneropenaeus indicus) for an isolate which showed biofilm-inhibitory activity (quorum quenching) against the pathogen V. parahaemolyticus DAHP1. The AHL-lactonase (AiiA) expressed by one of these, Bacillus licheniformis DAHB1, was characterised as having a broad-spectrum AHL substrate specificity and intrinsic resistance to the acid conditions of the shrimp intestine. Purified recombinant AiiA inhibited vibrio biofilm development in a cover slip assay and significantly attenuated infection and mortality in shrimps reared in a recirculation aquaculture system. Investigation of intestinal samples also showed that AiiA treatment also reduced vibrio viable counts and biofilm development as determined by confocal laser scanning microscopy (CLSM) imaging. These findings suggest that the B. licheniformis DAHB1 quorum-quenching AiiA might be developed for use as a prophylactic treatment to inhibit or reduce vibrio colonisation and mortality of shrimps in aquaculture

    Securing mechanism for the deployable column of the Hoop/Column antenna

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    The Column Longeron Latch (CLL) was designed and developed as the securing mechanism for the deployable, telescoping column of the Hoop/Column antenna. The column is an open lattice structure with three longerons as the principal load-bearing members. It is divided into telescoping sections that are deployed after the antenna is place in Earth orbit. The CLL provides a means to automatically lock the longeron sections into position during deployment as well as a means of unlocking the sections when the antenna is to be restowed. The CLL is a four bar linkage mechanism using the over center principle for locking. It utilizes the relative movement of the longeron sections to activate the mechanism during antenna deployment and restowing. The CLL design is one of the first mechanisms developed to meet the restowing requirements of spacecraft which will utilize the STS retrieval capability

    Latching mechanism for deployable/re-stowable columns useful in satellite construction

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    A column longeron latch assembly provides the securing mechanism for the deployable, telescoping column of a hoop/column antenna. The column is an open lattice structure with three longerons disposed 120 deg apart as the principle load bearing member. The column is deployed from a pair of eleven nested bays disposed on opposite sides of a center section under the influence of a motor-cable-pulley system. The longeron latch is a four bar linkage mechanism using the over-center principle for automatically locking the longeron sections into position during deployment. The latch is unlocked when the antenna is to be restowed. A spring pack disposed in the end of each longeron serves to absorb stress forces on the deployed column through the cam head piston and abutting latch from an adjacent longeron

    The Effect of Distance from NHL Affiliate on AHL Fan Attendance

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    This paper examines the effect of American Hockey League (AHL) teams locating closer to their National Hockey League (NHL) affiliates. With several AHL teams closing the distance (geographically) between their NHL affiliates for logistical purposes, I studied whether or not they will experience higher levels of fan support. I used data from all AHL teams between 2007 and 2017. I found a statistically insignificant negative relationship between proximity to NHL affiliate and average attendance in the AHL for all the teams. However, less popular AHL teams do experience higher levels of fan attendance when located closer to their NHL affiliate. Popular AHL teams often experience higher fan attendance figures regardless of their affiliation. While controlling other variables, I find that fans are drawn to AHL teams that have an older NHL affiliate. Also, NHL and AHL games appear to be substitute goods as AHL fan attendance increased by nearly 8 percent during the NHL lockout in 2012-2013. Finally, my results indicate that less popular AHL teams should relocate closer to their NHL affiliates in order to increase ticket sales

    Process Evolution based on Transformation of Algebraic High-Level Nets with Applications to Communication Platforms

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    Algebraic High-Level (AHL) nets are a well-known modelling technique based on Petri nets with algebraic data types, which allows to model the communication structure and the data flow within one modelling framework. Transformations of AHL-nets – inspired by the theory of graph transformations – allow in addition to modify the communication structure. Moreover, high-level processes of AHL-nets capture the concurrent semantics of AHL-nets in an adequate way. In this paper we show how to model the evolution of communication platforms and scenarios based on transformations of algebraic high-level nets and processes. All constructions and results are illustrated by a running example showing the evolution of Apache Wave platforms and scenarios. The evolution of platforms is modelled by the transformation of AHL-nets and that of scenarios by the transformation of AHL-net processes.Our main result is a construction for the evolution of AHL-processes based on the evolution of the corresponding AHL-net. This result can be used to transform scenarios in a communication platform according to the evolution of possibly multiple actions of the platform

    Modelling Evolution of Communication Platforms and Scenarios based on Transformations of High-Level Nets and Processes : Extended Version

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    Algebraic High-Level (AHL) nets are a well-known modelling technique based on Petri nets with algebraic data types, which allows to model the communication structure and the data flow within one modelling framework. Transformations of AHL-nets – inspired by the theory of graph transformations – allow in addition to modify the communication structure. Moreover, high-level processes of AHL-nets capture the concurrent semantics of AHL-nets in an adequate way. Altogether we obtain a powerful integrated formal specification technique to model and analyse all kinds of communication based systems, especially different kinds of communication platforms. In this paper we show how to model the evolution of communication platforms and scenarios based on transformations of Algebraic High-Level Nets and Processes. All constructions and results are illustrated by a running example showing the evolution of Apache Wave platforms and scenarios. The evolution of platforms is modelled by the transformation of AHL-nets and that of scenarios by the transformation of AHL-net processes. The first main result shows under which conditions AHL-net processes can be extended if the corresponding AHL-net is transformed. This result can be applied to show the extension of scenarios for a given platform evolution. The second main result shows how AHL-net processes can be transformed based on a special kind of transformation for AHL-nets, corresponding to action evolution of platforms. Finally, we briefly discuss the case of multiple action evolutions

    Characterization of Autoinducer Production in Bradyrhizobium japonicum

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    Quorum sensing allows bacteria to communicate with each other and coordinate their behavior with their surroundings. This communication uses autoinducers, such as Acyl-homoserine lactones (AHLs), which is produced and secreted by several strains of Bradyrhizobium japonicum. This study characterizes the production of AHL in specific strains of B. japonicum and describes the relationship between AHL production and a supposed AHL synthase gene in the B. japonicum genome. Polymerase Chain Reaction (PCR) was performed on various bacterium strains to amplify the synthase gene. Extraction of AHLs from B. japonicum culture supernatants were used to analyze AHL production using thin-layer chromatography (TLC). The results indicate that some strains of B. japonicum produce detectable AHLs of different sizes while other strains do not produce as much AHLs. Surprisingly, AHL production does not appear to correspond precisely with the presence of an AHL synthase gene, indicating more than one pathway for AHL synthesis

    Synthesis and analysis of stable isotope-labelled N-acyl homoserine lactones

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    Aliphatic aldehydes were deuterated at the alpha-position via a base-catalyzed exchange reaction with D2O. These deuterated building blocks were used for the synthesis of labelled analogues of quorum sensing signal molecules belonging to the three major classes of naturally occurring N-acylated homoserine lactones (AHLs), with the label on a non-enolizable and therefore stable position. Besides the application of these stable isotope-labelled AHLs as a labelled standard for analysis via isotope dilution mass spectrometry, these compounds can be used to study the metabolic fate of the fatty acid tail of the AHL-molecule. These isotope-labelled compounds were fully characterized and used to synthesize the deuterated analogues of two commonly occurring AHL-degradation products, a tetramic acid and a ring opened N-acyl homoserine
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