The inner mitochondrial membrane has been shown to have a novel structure that contains tubular components whose radii are on the order of 10 nm as well as comparatively flat regions [1]. The structural organization of mitochondria is important to understanding their functionality. We present a model that can account, thermodynamically, for the observed size of the tubules. The model contains t...

Cargo selection and export from the endoplasmic reticulum is mediated by the COPII coat machinery that includes the small GTPase Sar1 and the Sec23/24 and Sec13/31 complexes. We have analyzed the sequential events regulated by purified Sar1 and COPII coat complexes during synchronized export of cargo from the ER in vitro. We find that activation of Sar1 alone, in the absence of other cytosolic ...

Somatostatin modulates several renal tubular cell functions, including gluconeogenesis and proliferation. In this study, we demonstrate that cultured human proximal tubular epithelial cells (PTEC) express somatostatin. We also demonstrate positive and negative regulation of PTEC somatostatin production. We found that PTEC derived from 14 different human donors consistently expressed somatostati...

The segmentation of tubular tree structures like vessel systems in volumetric medical images is of vital interest for many medical applications. However, a diverse set of challenging objectives and problems is related to this task in different application domains. In this work, we develop and evaluate methods to address these issues. To accomplish the segmentation of heavily branched structures...

Gaussian distributions lie at the heart of popular tools for capturing structure in high dimensional data. Standard techniques employ as models arbitrary linear transformations of spherical Gaussians. In this paper, we present a simple extension to a class of non{ linear, volume preserving transformations which provides an e cient local description of curvature. The resulting generalized Gaussi...

We consider weak Gabriel drawings of unbounded degree trees in the three-dimensional space. We assume a minimum distance between any two vertices. Under the same assumption, there exists an exponential area lower bound for general graphs. Moreover, all previously known algorithms to construct (weak) proximity drawings of trees, generally produce exponential area layouts, even when we restrict o...

Creating new concepts from data is a hard problem in the development of cognitive architectures, but one that must be solved for the BICA community to declare success. Two concept generation algorithms are presented here that are appropriate to different levels of concept abstraction: statespace partitioning with decision trees and context-based similarity.

Before it can achieve wide acceptance, parallel computation must be made significantly easier to program. One of the main obstacles to this goal is the current usage of memory, both abstractly, by programmers, and concretely, by computer architects. In this paper, we present compiler technology for two novel computer architectures, and discuss how, on the one hand, many traditional, memory-base...

In today’s competitive, dynamic, and changing business environment, being able to collaborate globally within and beyond the enterprise borders is critical. Inter-Organizational Collaborations (IOCs) have been proposed as a response to the characteristics of highly competitive global business environments. So far, a number of reference models, frameworks, and ad hoc architectures related to som...