Bearing witness to uncorroborated trauma: The clinician's development of reflective belief.

Clinicians should not reflexively accept or reject as fact a client's initial report of uncorroborated abuse. However, by maintaining a neutral stance, clinicians may fall short of therapeutic honesty and transparency, may fail to promote reality testing, and may not perform the necessary step of bearing witness to the client's victimization. Using a case of dissociative identity disorder, this article proposes the careful development and sharing of the clinician's reflective belief in the (in)validity of reported trauma. This process may assist clients in (a) reclaiming a sense of integrated personal narrative memory and identity, (b) correcting cognitive distortions, or (c) both. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimization of fixed time polling schemes

This paper is concerned with the problem of deriving efficient operational rules for polling queues according to a fixed time polling scheme. A fixed time polling scheme specifies not only the visit order of the queues, but also the starting time for each visit. This problem arose from the need to efficiently collect files with call records from telecommunication switches. Using a simple approximation for the mean waiting times in a polling system with a non-cyclic visit order of the queues, we present an approach to the problem of minimizing a weighted sum of the mean waiting times at the various queues. This approach is tested via numerical experiments that are partly based on real network data.Part of O.J.B.'s research was supported by the European Grant BRA-QMIPS of CEC DG XIII.     

Assessing the value of Earth Observation for managing coral reefs: an example from the Great Barrier Reef

The Integrated Global Observing Strategy (IGOS, 2003) argues that further investments in Earth Observation information are required to improve coral reef protection worldwide. The IGOS Strategy does not specify what levels of investments are needed nor does it quantify the benefits associated with better-protected reefs. Evaluating costs and benefits is important for determining optimal investment levels and for convincing policy-makers that investments are required indeed. Few studies have quantitatively assessed the economic benefits of Earth Observation information or evaluated the economic value of information for environmental management. This paper uses an expert elicitation approach based on Bayesian Decision Theory to estimate the possible contribution of global Earth Observation to the management of the Great Barrier Reef. The Great Barrier Reef including its lagoon is a World Heritage Area affected by anthropogenic changes in land-use as well as climate change resulting in increased flows of sediments, nutrients and carbon to the GBR lagoon. Since European settlement, nutrient and sediment loads having increased 5-10 times and the change in water quality is causing damages to the reef. Earth Observation information from ocean and coastal color satellite sensors can provide spatially and temporally dense information on sediment flows. We hypothesize that Earth Observation improves decision-making by enabling better-targeted run-off reduction measures and we assess the benefits (cost savings) of this improved targeting by optimizing run-off reductions under different states of the world. The analysis suggests that the benefits of Earth Observation can indeed be substantial, depending on the perceived accuracy of the information and on the prior beliefs of decision-makers. The results indicate that increasing informational accuracy is the most effective way for developers of Earth Observation information to increase the added value of Earth Observation for managing coral reefs.     

Flooding and Drying in Discontinuous Galerkin Finite-Element Discretizations of Shallow-Water Equations. Part 1: One Dimension

Free boundaries in shallow-water equations demarcate the time-dependent water line between ‘‘flooded’’ and ‘‘dry’’ regions. We present a novel numerical algorithm to treat flooding and drying in a formally second-order explicit space discontinuous Galerkin finite-element discretization of the one-dimensional or symmetric shallow-water equations. The algorithm uses fixed Eulerian flooded elements and a mixed Eulerian–Lagrangian element at each free boundary. When the time step is suitably restricted, we show that the mean water depth is positive. This time-step restriction is based on an analysis of the discretized continuity equation while using the HLLC flux. The algorithm and its implementation are tested in comparison with a large and relevant suite of known exact solutions. The essence of the flooding and drying algorithm pivots around the analysis of a continuity equation with a fluid velocity and a pseudodensity (in the shallow water case the depth). It therefore also applies, for example, to space discontinuous Galerkin finite-element discretizations of the compressible Euler equations in which vacuum regions emerge, in analogy of the above dry regions. We believe that the approach presented can be extended to finite-volume discretizations with similar mean level and slope reconstruction.This revised version was published online in July 2005 with corrected volume and issue numbers.     

Segregation in thin films: the effect of mass balance and bonding to the support

The effect of mass balance on segregation in thin films is studied by minimizing the free energy of the film with respect to the composition of each layer for a fixed overall mole fraction. It is shown that the Bragg-Williams and quasi-chemical approximationsgive almost identical results. The effect of a difference in bond strength of the two components with the support is shown to lead to large variations in the composition of the outer film surface, even for thick (more than about 30 layers) films.     

Approximate analysis of exponential queueing systems with blocking

Summary A network of service stations Q ₀ Q ₁,...,Q_M is studied. Requests arrive at the centers according to independent Poisson processes; they travel through (part of) the network demanding amounts of service, with independent and negative exponentially distributed lengths, from those centers which they enter, and finally depart from the network. The waiting rooms or buffers at each service station in this exponential service system are finite. When the capacity at Q _i is reached, service at all nodes which are currently processing a request destined next for Q _i is instantaneously interrupted. The interruption lasts until the service of the request in the saturated node Q _i is. completed. This blocking phenomenon makes an exact analysis intractable and a numerical solution computationally infeasible for most exponential systems. We introduce an approximation procedure for a class of exponential systems with blocking and show that it leads to accurate approximations for the marginal equilibrium queue length distributions. The applicability of the approximation method may not be limited to blocking systems.Mathematical Sciences Department Postdoctoral Fellow 1978–79.     

The Identification of Small Molecule Inhibitors That Reduce Invasion and Metastasis of Aggressive Cancers

Transformed epithelial cells can activate programs of epithelial plasticity and switch from a sessile, epithelial phenotype to a motile, mesenchymal phenotype. This process is linked to the acquisition of an invasive phenotype and the formation of distant metastases. The development of compounds that block the acquisition of an invasive phenotype or revert the invasive mesenchymal phenotype into a more differentiated epithelial phenotype represent a promising anticancer strategy. In a high-throughput assay based on E-cadherin (re)induction and the inhibition of tumor cell invasion, 44,475 low molecular weight (LMW) compounds were screened. The screening resulted in the identification of candidate compounds from the PROAM02 class. Selected LMW compounds activated E-cadherin promoter activity and inhibited cancer cell invasion in multiple metastatic human cancer cell lines. The intraperitoneal administration of selected LMW compounds reduced the tumor burden in human prostate and breast cancer in vivo mouse models. Moreover, selected LMW compounds decreased the intra-bone growth of xenografted human prostate cancer cells. This study describes the identification of the PROAM02 class of small molecules that can be exploited to reduce cancer cell invasion and metastases. Further clinical evaluation of selected candidate inhibitors is warranted to address their safety, bioavailability and antitumor efficacy in the management of patients with aggressive cancers.     

From discrete particles to continuum fields near a boundary

An expression for the stress tensor near an external boundary of a discrete mechanical system is derived explicitly in terms of the constituents’ degrees of freedom and interaction forces. Starting point is the exact and general coarse graining formulation presented by Goldhirsch (Granul Mat 12(3):239–252, 2010), which is consistent with the continuum equations everywhere but does not account for boundaries. Our extension accounts for the boundary interaction forces in a self-consistent way and thus allows the construction of continuous stress fields that obey the macroscopic conservation laws even within one coarse-graining width of the boundary. The resolution and shape of the coarse-graining function used in the formulation can be chosen freely, such that both microscopic and macroscopic effects can be studied. The method does not require temporal averaging and thus can be used to investigate time-dependent flows as well as static or steady situations. Finally, the fore-mentioned continuous field can be used to define ‘fuzzy’ (very rough) boundaries. Discrete particle simulations are presented in which the novel boundary treatment is exemplified, including chute flow over a base with roughness greater than one particle diameter.