Novel steady state of a microtubule assembly in a confined geometry

We study the steady state of an assembly of microtubules in a confined volume, analogous to the situation inside a cell where the cell boundary forms a natural barrier to growth. We show that the dynamical equations for growing and shrinking microtubules predict the existence of two steady states, with either exponentially decaying or exponentially increasing distribution of microtubule lengths. We identify the regimes in parameter space corresponding to these steady states. In the latter case, the apparent catastrophe frequency near the boundary was found to be significantly larger than that in the interior. Both the exponential distribution of lengths and the increase in the catastrophe frequency near the cell margin is in excellent agreement with recent experimental observations.Comment: 8 pages, submitted to Phys. Rev.

Assessing the Cultural in Culturally Sensitive Printed Patient-Education Materials for Chinese Americans With Type 2 Diabetes

Type 2 diabetes affects Chinese Americans at an alarming rate. To address this health disparity, research in the area of cultural sensitivity and health literacy provide useful guidelines for creating culturally appropriate health education. In this article, we use discourse analysis to examine a group of locally-available, Chinese and English language diabetes print documents from a surface and deep structure level of culture. First, we compared these documents to research findings about printed health information to determine if and how these documents apply current best practices for health literacy and culturally appropriate health communication. Second, we examined how diabetes as a disease and diabetes management is being constructed. The printed materials addressed surface level culture through the use of Chinese language, pictures, foods and exercises. From a deeper cultural level, the materials constructed diabetes management as a matter of measurement and control that contrasted with previous research suggesting an alternative construction of balance. A nuanced assessment of both surface and deeper levels of culture is essential for creating health education materials that are more culturally appropriate and can lead to increase health literacy and improved health outcomes

The Galaxy Populations of X-Ray Detected, Poor Groups

(Abridged) We determine the quantitative morphology and star formation properties of galaxies in six nearby X-ray detected, poor groups using multi-object spectroscopy and wide-field R imaging. We measure structural parameters for each galaxy by fitting a PSF-convolved, two component model to their surface brightness profiles. To compare directly the samples, we fade, smooth, and rebin each galaxy image so that we effectively observe each galaxy at the same redshift (9000 km/s) and physical resolution (0.87h^(-1) kpc). We compare results for the groups to a sample of field galaxies. We find that: 1) Galaxies spanning a wide range in morphological type and luminosity are well-fit by a de Vaucouleurs bulge with exponential disk profile. 2) Morphologically classifying these nearby group galaxies by their bulge fraction (B/T) is fairly robust on average, even when their redshift has increased by up to a factor of four and the effective resolution of the images is degraded by up to a factor of five. 3) The fraction of bulge-dominated systems in these groups is higher than in the field (~50% vs. ~20%). 4) The fraction of bulge-dominated systems in groups decreases with increasing radius, similar to the morphology-radius (~density) relation observed in galaxy clusters. 5) Current star formation in group galaxies is correlated with significant morphological asymmetry for disk-dominated systems (B/T<0.4). 6) The group galaxies that are most disk-dominated (B/T<0.2) are less star forming and asymmetric on average than their counterparts in the field.Comment: Accepted for publication in the Astrophysical Journal (26 pages + 12 figures); Figs 1 & 2 also available at http://www.ucolick.org/~vy/astronomy/groups_figs.tar.g