Stroboscopic Reasearch

Contains research objectives

Stroboscopic Light Research

Contains research objectives.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 36-039-AMC-03200(E

Stroboscopic Research

Contains research objectives

Stroboscopic Research

Contains research objectives

Stroboscopic Research

Contains research objectives

Stroboscopic Research

Contains research objectives and reports on one research project.Woods Hole Oceanographic InstitutionU. S. Navy, Office of Naval Researc

Stroboscopic Research

Contains research objectives and reports on one research project

Underwater camera positioning by sonar

Originally issued as Reference No. 60-17A pulse sonar system is described for measuring the height above the bottom of an underwater camera and other equipment in the deep oceans. Using this method, cameras have been positioned for photography at depths to about 2,500 fathoms with a precision of about half a fathom. The measurement is achieved by a sonar "pinger" on the equipment, which sends precise 1 pulse-per- second signals to the surface both directly and by reflection from the bottom.Undersea Warfare Branch, Office of Naval Research Under Contract Nonr-1367(00) (NR-261-102

Transforming growth factor beta-regulated gene expression in a mouse mammary gland epithelial cell line

BACKGROUND: Transforming growth factor beta (TGF-β) plays an essential role in a wide array of cellular processes. The most well studied TGF-β response in normal epithelial cells is growth inhibition. In some cell types, TGF-β induces an epithelial to mesenchymal transition (EMT). NMuMG is a nontransformed mouse mammary gland epithelial cell line that exhibits both a growth inhibitory response and an EMT response to TGF-β, rendering NMuMG cells a good model system for studying these TGF-β effects. METHOD: A National Institutes of Aging mouse 15,000 cDNA microarray was used to profile the gene expression of NMuMG cells treated with TGF-β1 for 1, 6, or 24 hours. Data analyses were performed using GenePixPro and GeneSpring software. Selected microarray results were verified by northern analyses. RESULTS: Of the 15,000 genes examined by microarray, 939 were upregulated or downregulated by TGF-β. This represents approximately 10% of the genes examined, minus redundancy. Seven genes previously not known to be regulated by TGF-β at the transcriptional level (Akt and RhoB) or not at all (IQGAP1, mCalpain, actinin α3, Ikki, PP2A-PR53), were identified and their regulation by TGF-β verified by northern blotting. Cell cycle pathway examination demonstrated downregulation of cyclin D(2), c-myc, Id2, p107, E2F5, cyclin A, cyclin B, and cyclin H. Examination of cell adhesion-related genes revealed upregulation of c-Jun, α-actinin, actin, myosin light chain, p120cas catenin (Catns), α-integrin, integrin β5, fibronectin, IQGAP1, and mCalpain. CONCLUSION: Using a cDNA microarray to examine TGF-β-regulated gene expression in NMuMG cells, we have shown regulation of multiple genes that play important roles in cell cycle control and EMT. In addition, we have identified several novel TGF-β-regulated genes that may mediate previously unknown TGF-β functions

Robustness in large-scale random networks

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 73-76).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.We consider the issue of protection in very large networks displaying randomness in topology. We employ random graph models to describe such networks, and obtain probabilistic bounds on several parameters related to various protection schemes. In particular, we take the case of random regular networks for simplicity, where the degree of each node is the same, and consider the length of primary and backup paths in terms of the number of hops. First, for a randomly picked pair of nodes, we derive a lower bound on the average distance between the pair and discuss the tightness of the bound. In addition, noting that primary and protection paths form cycles, we obtain a lower bound on the average length of the shortest cycle around the pair. Finally, we show that the protected connections of a given maximum finite length are rare. We then generalize our network model so that different degrees are allowed according to some arbitrary distribution. Notably, we derive an upper bound on the mean number of non-finite length cycles in generalized random networks. More importantly, we show that most of the results in regular networks carry over with minor modifications, which significantly broadens the scope of networks to which our approach applies. Our main contributions are the following. First, we take an analytical approach by bringing the concept of randomness into network topologies that can provide concise rules to relate basic network parameters to robustness. Second, we establish analytical results for the length of backup paths for path and link-based protection schemes rather than for the efficiency of backup capacity, upon which most studies concentrate. Finally, we develop a unified framework for studying the issue of robustness in very general random networks with arbitrary degree distributions.by Minkyu Kim.S.M