Genetics and competing strategies in a threshold model for mail processing

Multi-agent algorithms inspired by the division of labour in social insects are applied to a problem of distributed mail retrieval in which agents must visit mail producing cities and choose between mail types under certain constraints.The efficiency (i.e. the average amount of mail retrieved per time step), and the flexibility (i.e. the capability of the agents to react to changes in the environment) are investigated both in static and dynamic environments. New rules for mail selection and specialisation are introduced and are shown to exhibit improved efficiency and flexibility compared to existing ones. We employ a genetic algorithm which allows the various rules to evolve and compete. Apart from obtaining optimised parameters for the various rules for any environment, we also observe extinction and speciation. From a more theoretical point of view, in order to avoid finite size effects, most results are obtained for large population sizes. However, we do analyse the influence of population size on the performance. Furthermore, we critically analyse the causes of efficiency loss, derive the exact dynamics of the model in the large system limit under certain conditions, derive theoretical upper bounds for the efficiency, and compare these with the experimental results.

Aberrant reactive oxygen and nitrogen species generation in rheumatoid arthritis (RA):causes and consequences for immune function, cell survival, and therapeutic intervention

The infiltration and persistence of hematopoietic immune cells within the rheumatoid arthritis (RA) joint results in elevated levels of pro-inflammatory cytokines, increased reactive oxygen (ROS) and -nitrogen (RNS) species generation, that feeds a continuous self-perpetuating cycle of inflammation and destruction. Meanwhile, the controlled production of ROS is required for signaling within the normal physiological reaction to perceived "foreign matter" and for effective apoptosis. This review focuses on the signaling pathways responsible for the induction of the normal immune response and the contribution of ROS to this process. Evidence for defects in the ability of immune cells in RA to regulate the generation of ROS and the consequence for their immune function and for RA progression is considered. As the hypercellularity of the rheumatoid joint and the associated persistence of hematopoietic cells within the rheumatoid joint are symptomatic of unresponsiveness to apoptotic stimuli, the role of apoptotic signaling proteins (specifically Bcl-2 family members and the tumor suppressor p53) as regulators of ROS generation and apoptosis are considered, evaluating evidence for their aberrant expression and function in RA. We postulate that ROS generation is required for effective therapeutic intervention.

The impact of transactional and relational strategies in business markets:an agenda for inquiry

The impetus for the special issue of Industrial Marketing Management is the importance of understanding the implications of transactional and relational strategies in business-to-business contexts. The objective of the special issue is to integrate conceptual and empirical research in this area. We highlight research that extends current thinking in the area to ensure that this special issue serves an impetus for future research on this important topic.

Compressed orally disintegrating tablets:excipients evolution and formulation strategies

Introduction: Orally disintegrating tablets (ODTs) have emerged as one of the novel solid oral dosage forms with a potential to deliver a wide range of drug candidates to both paediatric and geriatric patient populations. Of the plethora of available technologies, compression of excipients offers a cost-effective and translatable methodology for the manufacture of ODTs. Areas covered: The review is a modest endeavour from the authors to assemble literature published over the last couple of decades on formulation development of compressed ODT. It describes the main ODT excipients used since the introduction of this dosage form in the 1990s and explores the switch from cellulose-based excipients towards sugar/polyols. Furthermore, it unfolds the key properties of ODT fillers, binders and disintegrants with an emphasis on their advantages and drawbacks. The review also provides a critical assessment of the various strategies employed for performance enhancement of compressed ODT with a focus on the underlying mechanisms for fast disintegration and acceptable mechanical strength. Expert opinion: Recent increase in the total number of compression-based technologies for ODT development promises to reduce the manufacturing cost of this dosage form in the future. However, some of the developed methods may affect the stability of tablets due to susceptibility to moisture, collapse of pores or the generation of less stable polymorphs which require rigorous testing prior to commercialization. © 2013 Informa UK, Ltd.

Institutions, resources, and entry strategies in emerging economies

We investigate the impact of market-supporting institutions on business strategies by analyzing the entry strategies of foreign investors entering emerging economies. We apply and advance the institution-based view of strategy by integrating it with resource-based considerations. In particular, we show how resource-seeking strategies are pursued using different entry modes in different institutional contexts. Alternative modes of entry—greenfield, acquisition, and joint venture (JV)—allow firms to overcome different kinds of market inefficiencies related to both characteristics of the resources and to the institutional context. In a weaker institutional framework, JVs are used to access many resources, but in a stronger institutional framework, JVs become less important while acquisitions can play a more important role in accessing resources that are intangible and organizationally embedded. Combining survey and archival data from four emerging economies, India, Vietnam, South Africa, and Egypt, we provide empirical support for our hypotheses.

Occupational exposure to blood borne pathogens among healthcare workers and preventative strategies

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

Modelling and simulation strategies for the electric systems of large passenger aircraft

The simulation of a power system such as the More Electric Aircraft is a complex problem. There are conflicting requirements of the simulation, for example in order to reduce simulation run-times, power ratings that need to be established over long periods of the flight can be calculated using a fairly coarse model, whereas power quality is established over relatively short periods with a detailed model. An important issue is to establish the requirements of the simulation work at an early stage. This paper describes the modelling and simulation strategy adopted for the UK TIMES project, which is looking into the optimisation of the More Electric Aircraft from a system level. Essentially four main requirements of the simulation work have been identified, resulting in four different types of simulation. Each of the simulations is described along with preliminary models and results.

Stress, burnout and coping strategies in the emergency and intensive care hospital departments

Doctors and nurses working at the accident and emergency (A&E), and intensive care departments are at risk of burnout. They often spend substantial time in intense interactions with other people, centered on patients? health problems (physical, psychological and social) that may lead to feelings of anger, anxiety and frustration, and eventually to burnout. Burnout is a syndrome of emotional exhaustion, depersonalization and reduced personal accomplishment (Maslach & Jackson, 1981) The purpose of this chapter is to assess work stressors, burnout and stress-coping mechanisms among doctors and nurses at the A&E and intensive care departments. A quantitative design using the survey approach was used to collect data from a sample of 200 participants with a response rate of 71% (n=154) Work stressors were associated with burnout in both doctors and nurses. Workload was the most salient work stressor in the sample. Nurses experienced more stress (M=1.5, SD=0.4) than doctors (M=1.2, SD=0.4) in all the work stressor variables examined. The A&E department was reported as more stressful than the intensive care department. Avoidance-oriented and task-oriented coping were the most and the least frequently reported coping strategies respectively. Additionally, only emotion-oriented coping strategy was significantly different between doctors and nurses, and this strategy was also significantly positively correlated with all the variables in the adapted nursing stress scale, and the three burnout variables. Death and dying was most strongly correlated with emotion-oriented coping. This chapter provides an assessment of stress, burnout and coping experienced by both doctors and nurses within the A&E and intensive care departments. Methods that may mitigate stress in these environments may be adequate staffing, supportive management, stress management programs, as well as improvement in communication strategies between doctors and nurses.

A robust preference for cheap-and-easy strategies over reliable strategies when verifying personal memories

People depend on various sources of information when trying to verify their autobiographical memories. Yet recent research shows that people prefer to use cheap-and-easy verification strategies, even when these strategies are not reliable. We examined the robustness of this cheap strategy bias, with scenarios designed to encourage greater emphasis on source reliability. In three experiments, subjects described real (Experiments 1 and 2) or hypothetical (Experiment 3) autobiographical events, and proposed strategies they might use to verify their memories of those events. Subjects also rated the reliability, cost, and the likelihood that they would use each strategy. In line with previous work, we found that the preference for cheap information held when people described how they would verify childhood or recent memories (Experiment 1); personally-important or trivial memories (Experiment 2), and even when the consequences of relying on incorrect information could be significant (Experiment 3). Taken together, our findings fit with an account of source monitoring in which the tendency to trust one’s own autobiographical memories can discourage people from systematically testing or accepting strong disconfirmatory evidence.

ERK5 is required for VEGF-mediated survival and tubular morphogenesis of primary human microvascular endothelial cells

Extracellular signal-regulated kinase 5 (ERK5) is activated in response to environmental stress and growth factors. Gene ablation of Erk5 in mice is embryonically lethal as a result of disruption of cardiovascular development and vascular integrity. We investigated vascular endothelial growth factor (VEGF)-mediated ERK5 activation in primary human dermal microvascular endothelial cells (HDMECs) undergoing proliferation on a gelatin matrix, and tubular morphogenesis within a collagen gel matrix. VEGF induced sustained ERK5 activation on both matrices. However, manipulation of ERK5 activity by siRNA-mediated gene silencing disrupted tubular morphogenesis without impacting proliferation. Overexpression of constitutively active MEK5 and ERK5 stimulated tubular morphogenesis in the absence of VEGF. Analysis of intracellular signalling revealed that ERK5 regulated AKT phosphorylation. On a collagen gel, ERK5 regulated VEGF-mediated phosphorylation of the pro-apoptotic protein BAD and increased expression of the anti-apoptotic protein BCL2, resulting in decreased caspase-3 activity and apoptosis suppression. Our findings suggest that ERK5 is required for AKT phosphorylation and cell survival and is crucial for endothelial cell differentiation in response to VEGF.