Continuous Workout Mortgages

This paper models Continuous Workout Mortgages (CWMs) in an economic environment with refinancings and prepayments by employing a market-observable variable such as the house price index of the pertaining locality. Our main results include: (a) explicit modelling of repayment and interest-only CWMs; (b) closed form formulae for mortgage payment and mortgage balance of a repayment CWM; (c) a closed form formula for the actuarially fair mortgage rate of an interest-only CWM. For repayment CWMs we extend our analysis to include two negotiable parameters: adjustable "workout proportion" and adjustable "workout threshold." These results are of importance as they not only help understanding the mechanics of CWMs and estimating key contract parameters. These results are of importance as they not only help in the understanding of the mechanics of CWMs and estimating key contract parameters, but they also provide guidance on how to enhance the resilience of the financial architecture and mitigate systemic risk.Continuous Workout Mortgage (CWM), Repayment, Interest-only, House price index, Prepayment intensity, Cap and floor on continuous flow

The option and decision to repurchase stock

Journal ArticleThis is the accepted version of the following article: The option and decision to repurchase stock. Financial Management, Volume 43, Issue 4, pages 833–855, Winter 2014 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/fima.12054/abstractOpen-market repurchase programs provide firms with the flexibility to manage the cash and risk aspects of their operations. We examine at which stage cash and risk matter in the typical stages of a repurchase program: announcement, implementation, and withdrawal. Cash and risk considerations appear to matter only at the implementation stage, and partially negate the traditional signaling effect around program announcement

Option-Implied Volatilities and Stock Returns: <i>Evidence from Industry-Neutral Portfolios</i>

Recent studies demonstrate the profitability of stock portfolios constructed according to implied volatility measures inferred from option prices. This article examines industry effects on such portfolios’ performance. Results show that quintile portfolios constructed using volatility skew and volatility spread are subject to substantial industry effects, which are particularly strong during market turbulence. The authors form industry-neutral portfolios and compare their performances to those of full-universe portfolios that do not consider industry exposure. Results show significant improvement when portfolio strategies are implemented in an industry-neutral manner, based on either volatility skew or volatility spread

Melanoma stem cells – are there devils in the detail?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79226/1/j.1755-148X.2010.00750.x.pd

Progress in understanding melanoma propagation

Melanoma, like most cancers, is a disease that wreaks havoc mostly through its propensity to spread and establish secondary tumors at sites that are anatomically distant from the primary tumor. The consideration of models of cancer progression is therefore important to understand the essence of this disease. Previous work has suggested that melanoma may propagate according to a cancer stem cell (CSC) model in which rare tumorigenic and bulk non‐tumorigenic cells are organized into stable hierarchies within tumors. However, recent studies using assays that are more permissive for revealing tumorigenic potential indicate that it will not be possible to cure patients by focusing research and therapy on rare populations of cells within melanoma tumors. Studies of the nature of tumorigenic melanoma cells reveal that these cells may gain a growth, metastasis and/or therapy resistance advantage by acquiring new genetic mutations and by reversible epigenetic mechanisms. In this light, efforts to link the phenotypes, genotypes and epigenotypes of melanoma cells with differences in their in vivo malignant potential provide the greatest hope of advancing the exciting progress finally being made against this disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135709/1/mol2201045451.pd

"Disastrous Adoption"? Representations of Fetal Alcohol Syndrome and Disability in Recent Native North American Writing

Peer reviewe

Stakeholder engagement in the study and management of invasive alien species

Invasive alien species are a major driver of global environmental change and a range of management interventions are needed to manage their effects on biodiversity, ecosystem services, human well-being and local livelihoods. Stakeholder engagement is widely advocated to integrate diverse knowledge and perspectives in the management of invasive species and to deal with potential conflicts of interest. We reviewed the literature in the ISI Web of Science on stakeholder engagement (the process of involving stakeholders (actors) in decision making, management actions and knowledge creation) in invasion science to assess and understand what has been done (looking at approaches and methodologies used, stakeholders involved, and outcomes from engagement) and to make recommendations for future work. Research on stakeholder engagement in invasion science has increased over the last decade, helping to improve scientific knowledge and contributing towards policy formulation and co-implementation of management. However, many challenges remain and engagement could be made more effective. For example, most studies engage only one stakeholder group passively using questionnaires, primarily for assessing local knowledge and perceptions. Although useful for management and policy planning, these stakeholders are not active participants and there is no two-way flow of knowledge. To make stakeholder involvement more useful, we encourage more integrative and collaborative engagement to (1) improve co-design, co-creation and co-implementation of research and management actions; (2) promote social learning and provide feedback to stakeholders; (3) enhance collaboration and partnerships beyond the natural sciences and academia (interdisciplinary and transdisciplinary collaboration); and (4) discuss some practical and policy suggestions for improving stakeholder engagement in invasion science research and management. This will help facilitate different stakeholders to work better together, allowing problems associated with biological invasions to be tackled more holistically and successfully

Progress in paleoclimate modeling

International audienceThis paper briefly surveys areas of paleoclimate modeling notable for recent progress. New ideas, including hypotheses giving a pivotal role to sea ice, have revitalized the low-order models used to simulate the time evolution of glacial cycles through the Pleistocene, a prohibitive length of time for comprehensive general circulation models (GCMs). In a recent breakthrough, however, GCMs have succeeded in simulating the onset of glaciations. This occurs at times (most recently, 115 kyr B.P.) when high northern latitudes are cold enough to maintain a snow cover and tropical latitudes are warm, enhancing the moisture source. More generally, the improvement in models has allowed simulations of key periods such as the Last Glacial Maximum and the mid-Holocene that compare more favorably and in more detail with paleoproxy data. These models now simulate ENSO cycles, and some of them have been shown to reproduce the reduction of ENSO activity observed in the early to middle Holocene. Modeling studies have demonstrated that the reduction is a response to the altered orbital configuration at that time. An urgent challenge for paleoclimate modeling is to explain and to simulate the abrupt changes observed during glacial epochs (i.e., Dansgaard-Oescher cycles, Heinrich events, and the Younger Dryas). Efforts have begun to simulate the last millennium. Over this time the forcing due to orbital variations is less important than the radiance changes due to volcanic eruptions and variations in solar output. Simulations of these natural variations test the models relied on for future climate change projections. They provide better estimates of the internal and naturally forced variability at centennial time scales, elucidating how unusual the recent global temperature trends are