On the nuclear dimension of certain UCT-Kirchberg algebras

We give a partial answer to the question for the precise value of the nuclear dimension of UCT-Kirchberg algebras raised by W. Winter and J. Zacharias. It is shown that every Kirchberg algebra in the UCT-class with torsion free $K_1$-group has nuclear dimension 1.Comment: 9 page

Biomimetic and Biophysical Approach to Profile Metastatic Cancer Cell Migration

Honors Research ScholarshipCancer metastasis is a complex process by which cells in a primary tumor acquire an aggressive phenotype, and travel to distant, secondary sites in the body. One aspect of cancer metastasis is cell migration toward the vascular system, called invasion. Multiple modalities of single cell invasion exist, including amoeboid migration and mesenchymal migration. Amoeboid migration is less well understood, and in particular, the forces involved in amoeboid migration have yet to be fully elucidated at a subcellular scale. Cellular traction force microscopy, or CTFM, is one method used to probe migration forces. However, this approach is largely limited to two dimensions, and is limited by the size of the pillars on the substrate. To address these limitations, we developed a system using microfluidics and DNA origami capable of real-time force measurement of cell migration on a subcellular scale with a 10 pN resolution. Microfluidic devices were made using soft lithography and replica molding in our laboratory. DNA origami were made using protocols developed by Michael Hudoba and Dr. Carlos Castro in the Nanoengineering and Biodesign Laboratory. The devices were imaged using TIRF microscopy to study dwell times of the sensors in the open and closed states, and the devices were analyzed with an AFM to determine that they are best suited for measuring shear forces. Further, the presence of streptavidin protein was found to have a significant effect on DOFS binding with a p-value less than 0.05. DOFS concentrations around 1 nM were found to provide the most coverage while minimizing structure aggregation. Thus, our microfluidic devices are able to be functionalized with DNA origami force sensors with a high degree of attachment. This platform is thus capable of measuring cell migration and adhesion forces, and future work should harness this system to create 3D maps of cell migration to gain insight into invasion.Institute for Materials ResearchSecond-Year Transformational Experience Program (STEP)A one-year embargo was granted for this item.Academic Major: Biomedical Engineerin

Slow Money Dissemination

A model of limited participation in the asset market is developed, in which varieties of consumption bundles are purchased sequentially. By this, heterogeneity in money holdings and in the effective elasticity of substitution of consumers arises, which affects optimal markups chosen by oligopolistic firms. The model generates a short-term inflation-output trade off, although all firms can set their optimal price each period and no informational problems exist. The responses are persistent even after a one-time monetary shock due to an internal propagation mechanism that stems from the slow dissemination of newly injected money. Furthermore, a liquidity effect, countercyclical markups, procyclical profits and marginal costs after monetary shocks are obtained. The model is simple and tractable, such that analytical results for the linearized model can be derived.Limited Participation, Countercyclical Markups, Liquidity Effect Phillips Curve, Oligopolistic Competition

Classical vgr≠cv_{gr} \neq c solutions of Maxwell equations and the tunneling photon effect

We propose a very simple but general method to construct solutions of Maxwell equations propagating with a group velocity $v_{gr} \neq c$. Applications to wave guides and a possible description of the known experimental evidences on photonic tunneling are discussed.Comment: 11 pages, Latex2e; to be published in Phys. Lett.

Heterogeneous consumers, segmented asset markets,and the effects of monetary policy

This paper examines the implications of segmented assets markets for the real and nominal effects of monetary policy. I develop a model, in which varieties of consumption bundles are purchased sequentially. Newly injected money thus disseminates slowly through the economy via second-round effects and induces a non-degenerate, long-lasting heterogeneity in wealth. As a result, the effective elasticity of substitution differs across households, affecting optimal markups chosen by producers. In line with empirical evidence, the model predicts a short-term inflation-output trade-off, a liquidity effect, countercyclical markups, and procyclical profits and wages after monetary shocks.Segmented Asset Markets, Monetary Policy, CountercyclicalMarkups Liquidity Effect, Limited Participation