Conceptualization and implementation of a multi-agent model to simulate whale-watching tours in the St. Lawrence Estuary in Quebec, Canada

The Saguenay St. Lawrence Marine Park (SSLMP) and the adjacent Marine Protected Area (MPA) in the St. Lawrence Estuary, in Quebec, cover a territory of exceptional biodiversity including 12 species of marine mammals, nearly half of which are considered to be endangered species. Whale-watching trips and other human activities related to commercial shipping, tourism, and recreation generate very intensive traffic in the area, which pose cumulative threats to the marine wildlife. This study has been undertaken in collaboration with the Marine Park and the MPA managers to develop a multi-agent system (MAS) to investigate the interactions between the traffic and the marine mammals in the estuary. This paper describes the first prototype version of the proposed MAS model where the focus is on the whale-watching boats. It discusses the conceptual model with its principal components: the physical environment and the boat agents and whale entities, and the implementation of the model with the behavior rules of the agents. In this version of the MAS, the whale-watching boats are represented as cognitive agents while the whales are simple reactive entities. The prototype model was implemented in the agent-based modeling platform RePast. An index, the happiness factor (i.e., the ratio of whale observation time over the trip duration) was designed to measure how successful the boat agents are in achieving their goal. Simulations were run to assess different decision strategies of the boat agents and their impacts on the whales. Results show that cooperative behavior that involves a combination of innovator and imitator strategies yields a higher average happiness factor over non-cooperative, purely innovators, behavior. However, this cooperative behavior creates increased risk for the whale populations in the estuary.     

Assessment of Load Transfer and Load Distribution in Bridges Utilizing FRP Panels

A primary means of demonstrating the feasibility and effectiveness of fiber-reinforced polymer (FRP) composite bridge materials is via in situ bridge load testing. For this study, the prescribed or assumed design factors for each of the study bridges were compared to those exhibited by the performance of the bridge. Specifically, the wheel load distribution factors and impact factors as defined by AASHTO were considered in order to assess the load transfer and distribution in structures utilizing FRP panels. The in situ testing configurations for the study bridges are outlined, including the truck and instrumentation placement to obtain the desired information. Furthermore, comparisons were drawn between the design values for deflection and those experienced by the structures during testing. It was found that although the deflections exhibited by the bridges were well within the design limits, further research is needed to be able to prescribe bridge design factors for FRP panels.     

Dopamine D? receptor stimulation of the nucleus accumbens or the medial preoptic area promotes the onset of maternal behavior in pregnancy-terminated rats.

There is good evidence that interference with the mesolimbic dopamine (DA) system results in impaired maternal responding in postpartum female rats. However, whether activation of the mesolimbic DA system is capable of promoting maternal behavior has not been investigated. This study examined whether increasing DA activity in various brain regions of pregnancy-terminated, naive female rats would stimulate the onset of maternal behavior. Experiments 1 and 2 examined the effects of microinjection of various doses (0, 0.2, or 0.5 μg/0.5 μl/side) of a D? DA receptor agonist, SKF 38393, or a D? DA receptor agonist, quinpirole, into the nucleus accumbens (NA) on latency to show full maternal behavior, and Experiment 3 determined the effects of SKF 38393 injection into a control site. Finally, because the medial preoptic area (MPOA) is also important for maternal behavior, receives DA input, and expresses DA receptors, the authors examined whether microinjection of SKF 38393 into MPOA was capable of stimulating the onset of maternal behavior. Results indicated that microinjection of SKF 38393 into either the NA or the MPOA facilitates maternal responding in pregnancy-terminated rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overflow probability in shared cell switched buffers

The ubiquity of the cell switching technique is a clear indication of its continued importance for the future of telecommunications worldwide. The performance of shared buffers in cell switches provides substantial improvement over switches with separate output buffers. The conventional approach to shared buffer analysis is numerical convolution; however, previous work provides an analytical solution based on the Chernoff bound. In this paper we develop a new closed-form expression for the cell loss probability in the shared buffer that offers superior accuracy, enhanced simplicity, and better generality     

New developments in fire retardant non‐halogen aromatic phosphates

Akzo Nobel Chemicals has recently introduced on the market an aromatic oligomeric phosphate (BDP) based on Bisphenol A. This product shows higher thermal and hydrolytic stability than other aryl phosphates. It provides similar or better fire retardant performance than an oligomeric phosphate (RDP) based on resorcinol. Fire retardant formulations with BDP based on polycarbonate/ABS plastic (PC/ABS) blend, polyphenylene oxide/high impact polystyrene (PPO/HIPS) blend, and HIPS alone show similar or better physical properties than those obtained with RDP. Upon thermal decomposition of the fire retarded polymers containing BDP, phosphorus tends to accumulate in the solid residue, a result which indicates that the primary fire retardant action of BDP is likely to occur in the condensed phase.     

Comparison of the univariate and multivariate methods in the optimization of experimental conditions for determining Cu, Pb, Ni and Cd in biodiesel by GFAAS

Experimental design was used as a tool to define the optimum pyrolysis and atomization temperatures for four analytes (Cu, Pb, Ni and Cd) in biodiesel samples. Two chemical modifiers (Pd + Mg and W) and two distinct sample preparation procedures (microemulsion and wet digestion in a focused microwave system) were also investigated. The pyrolysis and atomization temperatures were optimized using 2⁴ factorial design for Cu, Pb, Ni and Cd, with 16 assays carried out for each analyte. The results for Cu and Pb indicated that variables of sample preparation for digestion by focused microwave was the most important one for both analytes. The pyrolysis and atomization temperatures applied were 1000 °C and 2200 °C for Cu and 500 °C and 2000 °C for Pb. None of the variables analyzed here were important for Ni, and the pyrolysis and atomization temperatures chosen for this element were 800 °C and 2300 °C. A different factorial design was used for Cd. The variables of medium and modifier were not important for this element, and the lowest temperatures, Tp-500 °C and Ta-1400 °C, were chosen based on this second design. The importance of factorial design in the simultaneous optimization of several variables studied by GFAAS was confirmed, for it involves fewer experiments and hence, lower costs, greater speed and higher efficiency.     

What's in a manner of speaking? Children's sensitivity to partner-specific referential precedents.

Do young children form “referential pacts”? If a person has referred to an object with a certain term (e.g., the horse), will children expect this person to use this term in the future but allow others to use a different expression (e.g., the pony)? One hundred twenty-eight children between 3 and 5 years old co-operated with an experimenter (E1) to move toys to new locations on a shelf. E1 established referential terms for all toys in a warm-up game. Then, either the original partner, E1, or a new partner, E2, played a second game with the same toys. In this game, the experimenters referred to toys using either their original terms from the warm-up game or new terms. Children were slower to react to new terms than old, and this difference in reaction times was greater in the original partner condition (but only on the first trial). Children sometimes protested at the use of new terms, doing so regardless of their interlocutor's identity. We contrast these findings with those for adults and discuss their implications for the debate regarding the nature of referential pacts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)