Arabian adventures

The United Arab Emirates (UAE) is one of the world’s most rapidly urbanising countries. Despite the recent downturn in the economy, the region continues to undergo rapid development, particularly around Abu Dhabi and Dubai. Consequently the country is host to many major civil engineering projects including the world’s tallest building, artificial offshore islands, new international airports, metro systems and high-speed rail networks

Employer branding and multiple identities in the hotel industry

Service employees have long been seen as the interface between an organisation and its customers. This is particularly the case in the hospitality industry where the actions of the employees are often seen as the manifestation of the brand and the major contributor to the reputation of a hotel. Employees have become the most valuable asset of hotel companies, a company’s success will depend greatly on building a work environment that attracts, meets and exceeds employees’ expectations

A Theory of Rule Development

This article develops a model with endogenously coarse rules. A principal hires an agent to take an action. The principal knows the optimal state-contingent action, but cannot communicate it perfectly due to communication constraints. The principal can use previously realized states as examples to define rules of varying breadth. We analyze how rules are chosen under several assumptions about how rules can be amended. We explore the inefficiencies that arise and how they depend on the ability to refine rules, the principal’s time horizon and patience, and other factors. Our model exhibits path dependence in that the efficacy of rule development depends on the sequence of realizations of the state. We interpret this as providing a foundation for persistent performance differences between similar organizations and explore the role of different delegation structures in ameliorating the effects of bounded communication.Sloan School of Management (Program on Innovation in Markets and Organizations)National Science Foundation (U.S.) (SES-0550897

Evaluating cloud database migration options using workload models

A key challenge in porting enterprise software systems to the cloud is the migration of their database. Choosing a cloud provider and service option (e.g., a database-as-a-service or a manually configured set of virtual machines) typically requires the estimation of the cost and migration duration for each considered option. Many organisations also require this information for budgeting and planning purposes. Existing cloud migration research focuses on the software components, and therefore does not address this need. We introduce a two-stage approach which accurately estimates the migration cost, migration duration and cloud running costs of relational databases. The first stage of our approach obtains workload and structure models of the database to be migrated from database logs and the database schema. The second stage performs a discrete-event simulation using these models to obtain the cost and duration estimates. We implemented software tools that automate both stages of our approach. An extensive evaluation compares the estimates from our approach against results from real-world cloud database migrations

Towards Platform Independent Database Modelling in Enterprise Systems

Enterprise software systems are prevalent in many organisations, typically they are data-intensive and manage customer, sales, or other important data. When an enterprise system needs to be modernised or migrated (e.g. to the cloud) it is necessary to understand the structure of this data and how it is used. We have developed a tool-supported approach to model database structure, query patterns, and growth patterns. Compared to existing work, our tool offers increased system support and extensibility which is vital for use in industry. Standardisation and platform independence is ensured by producing models conforming to the Knowledge Discovery Metamodel and Software Metrics Metamodel

PON1 status does not influence cholinesterase activity in Egyptian agricultural workers exposed to chlorpyrifos.

Animal studies have shown that paraoxonase 1 (PON1) genotype can influence susceptibility to the organophosphorus pesticide chlorpyrifos (CPF). However, Monte Carlo analysis suggests that PON1 genotype may not affect CPF-related toxicity at low exposure conditions in humans. The current study sought to determine the influence of PON1 genotype on the activity of blood cholinesterase as well as the effect of CPF exposure on serum PON1 in workers occupationally exposed to CPF. Saliva, blood and urine were collected from agricultural workers (n=120) from Egypt's Menoufia Governorate to determine PON1 genotype, blood cholinesterase activity, serum PON1 activity towards chlorpyrifos-oxon (CPOase) and paraoxon (POase), and urinary levels of the CPF metabolite 3,5,6-trichloro-2-pyridinol (TCPy). The PON1 55 (P≤0.05) but not the PON1 192 genotype had a significant effect on CPOase activity. However, both the PON1 55 (P≤0.05) and PON1 192 (P≤0.001) genotypes had a significant effect on POase activity. Workers had significantly inhibited AChE and BuChE after CPF application; however, neither CPOase activity nor POase activity was associated with ChE depression when adjusted for CPF exposure (as determined by urinary TCPy levels) and stratified by PON1 genotype. CPOase and POase activity were also generally unaffected by CPF exposure although there were alterations in activity within specific genotype groups. Together, these results suggest that workers retained the capacity to detoxify chlorpyrifos-oxon under the exposure conditions experienced by this study population regardless of PON1 genotype and activity and that effects of CPF exposure on PON1 activity are minimal

Outliers from the Mass--Metallicity Relation II: A Sample of Massive Metal-Poor Galaxies from SDSS

We present a sample of 42 high-mass low-metallicity outliers from the mass--metallicity relation of star-forming galaxies. These galaxies have stellar masses that span log(M_*/M_sun) ~9.4 to 11.1 and are offset from the mass--metallicity relation by -0.3 to -0.85 dex in 12+log(O/H). In general, they are extremely blue, have high star formation rates for their masses, and are morphologically disturbed. Tidal interactions are expected to induce large-scale gas inflow to the galaxies' central regions, and we find that these galaxies' gas-phase oxygen abundances are consistent with large quantities of low-metallicity gas from large galactocentric radii diluting the central metal-rich gas. We conclude with implications for deducing gas-phase metallicities of individual galaxies based solely on their luminosities, specifically in the case of long gamma-ray burst host galaxies.Comment: Accepted for publication in ApJ; 11 pages, 11 figure