Periods of ownership in shipping : patterns and influences

PhD ThesisIn modern shipping the use of sophisticated investment valuation tools is not the rule but the exception and investment decisions are often based on the useful economic life of the asset, which can be misleading. The purpose of this research is to investigate periods of ownership in shipping based on evidence from the commercial history of vessels built between 1987 and 2007 in order to determine the likely investment horizon for a vessel owner. The research aims to provide an insight into the strategies and practices adopted by shipping professionals in terms of sale and purchase policies of assets. This will facilitate marine service and equipment providers, such as sale and purchase brokers and retrofitted equipment and systems manufacturers, in targeting customers. The analysis incorporates ship and company level characteristics as well as economic indicators and is focused on the three main ship types – bulk carriers, tankers and container ships. In order to fully address the nature of the data on periods of ownership, also known as time-to-event data, a variety of statistical techniques used in demographical studies and in biomedicine have been employed to: (i) describe patterns of ownership in shipping; and (ii) establish whether certain characteristics at the ship and company levels as well as economic indicators influence periods of ownership. Furthermore, in depth interviews with shipping professionals were also conducted to provide further insights. In this research the commercial records of 3,908 vessels of 30,000 dwt and above have been examined resulting in 8,042 changes of ownership recorded. Data on 1,125 companies has been gathered based on the ownership history of 2,000 vessels from the sample. The results reveal that different sets of characteristics affect the decision for a ship to be sold by each owner in the succession of owners comprising the commercial history of a vessel. The most likely scenarios for the economic lives of vessels are identified and analysed based on ship and company characteristics

The influence of ambient cure chemistry and stoichiometry on epoxy coating surfaces

The surface properties of epoxy resin coatings influence their function as substrates for subsequent coats. Variation in ambient cure conditions (temperature and relative humidity, RH), stoichiometry (ratio of epoxy: amine) and delay time between epoxy component mixing and film casting (“induction time”) significantly altered the surface properties of ambient cured epoxy resin coatings (Dow Epoxy Novolac D.E.N. 431, resorcinol diglycidyl ether and 4,4-diaminodicyclohexylmethane). Gravimetric analysis showed that increasing induction time significantly reduced surface layer formation (carbamation) of cured epoxy resin coatings at 80% RH but had no measurable effect at 40% RH and below. RMS surface roughness increased with increasing RH and decreased with increasing induction time and ambient cure temperature, at two stoichiometric extremes. However, the net change in surface area arising from these conditions was not sufficient to significantly alter the equilibrium contact angles or wetting regime. We conclude that the observed significant variation in surface wettability was more likely to depend on variation in surface chemistry than roughness; stoichiometry was the variable which most significantly influenced surface wettability, average void volume and fractional free volume, while cure temperature significantly influenced the extent of cure at both stoichiometries. Off-stoichiometry formulation and elevated ambient cure temperature significantly increased system average void volume while fractional free volume decreased, which may be significant for the barrier properties of the final coating

A Dual Frailty Model for Lifetime Analysis in Maritime Transportation

We consider changes in ownership of commercial shipping vessels from an event history perspective. Each change in ownership can be influenced by the properties of the vessel itself, its age and history to date, the characteristics of both the seller and the buyer, and time-varying market conditions. Similar factors can aect the process of deciding when to scrap the vessel as no longer being economically viable. We consider a multi-state approach in which states are dened by the owning companies, a sale marks a transition, and scrapping of the vessel corresponds to moving to an absorbing state. We propose a dual frailty model that attempts to capture unexplained heterogeneity in the data, with one frailty term for the seller and one for the buyer. We describe a Monte Carlo Markov chain estimation procedure and verify its accuracy through simulations. We investigate the consequences of mistakenly ignoring frailty in these circumstances. We compare results from the frailty analysis with an analysis using xed eects only

The safety of herbal medicine: myth or reality

IntroductionThe use of herbal medicines continues to expand rapidly. Many people now take herbal medicines or herbal products for their health in different cases due to their low price and better compatibility with the human body. They are also regarded as minimal risk in terms of side effects, although researches on herbal medicine safety are still not broad or deep enough. Unfortunately, there are limited available published data regarding the potential toxicity of a variety of plant substances commonly used in herbal drugs.Aim The aim of this paper is to review safety issues associated with the use of herbal products.Materials and Methods We used the following web databases - Pubmed, ScienceDirect and Google Scholar. Results More and more reports have been documenting the apparent increasing popularity of herbal medicines. Although many popular herbal products are thought to be safe, a lot of unexpected effects of some of them are already described in the literature. Both minor and major toxicities have been determined, including emesis, hypersensitivity reactions, cardiovascular events, neurological dysfunction, hepatic and renal failure, and also development of malignant disease.Conclusion Our research shows the importance of pharmacists being aware of what nonprescription herbal medications their patients are taking and being informed of the potential side and toxic effects of these agents

Chemical Composition and Disruption of Quorum Sensing Signaling in Geographically Diverse United States Propolis

Propolis or bee glue has been used for centuries for various purposes and is especially important in human health due to many of its biological and pharmacological properties. In this work we showed quorum sensing inhibitory (QSI) activity of ten geographically distinct propolis samples from the United States using the acyl-homoserine lactone- (AHL-) dependent Chromobacterium violaceum strain CV026. Based on GC-MS chemical profiling the propolis samples can be classified into several groups that are as follows: (1) rich in cinnamic acid derivatives, (2) rich in flavonoids, and (3) rich in triterpenes. An in-depth analysis of the propolis from North Carolina led to the isolation and identification of a triterpenic acid that was recently isolated from Hondurian propolis (Central America) and ethyl ether of p-coumaric alcohol not previously identified in bee propolis. QSI activity was also observed in the second group US propolis samples which contained the flavonoid pinocembrin in addition to other flavonoid compounds. The discovery of compounds that are involved in QSI activity has the potential to facilitate studies that may lead to the development of antivirulence therapies that can be complementary and/or alternative treatments against antibiotic resistant bacterial pathogens and/or emerging pathogens that have yet to be identified