Physical Sciences and Mathematics Commons^™

Phase Contrast Imaging Using Photothermally Induced Phase Transitions In Liquid Crystals, Chandra S. Yelleswarapu, Sri-Rajasekhar Kothapalli, Francisco J. Aranda, D.V.G.L.N. Rao, Yvonne Vaillancourt, Brian R. Kimball

Physics Faculty Publications

Phase contrast imaging is performed for live biological species using photothermal induced birefringence in dye doped liquid crystals. Using typical 4-f configuration, when liquid crystal cell is at back focal plane of Fourier lens, low spatial frequencies at center of Fourier spectrum are intense enough to induce local liquid crystal molecules into isotropic phase, whereas high spatial frequencies on the edges are not intense enough and remain in anisotropic phase. This results in π/2 phase difference between high and low spatial frequencies. This simple, inexpensive, all-optical, user-friendly, self-adaptive phase contrast imaging technique using low-power laser offers several distinct advantages.

Human Development And Resources Use In The Coastal Zone: Influences On Human Health, Robert E. Bowen, Anamarija Frankic, Mary E. Davis

Environmental, Earth, and Ocean Sciences Faculty Publication Series

Coastal watersheds and nearshore marine areas are the most valuable and dynamic places on Earth. Human population growth is great in these regions, which are home to some of the most sensitive habitats in the world. Coastal areas provide more than half of the overall service value derived from the global environment (Costanza et al., 1997). Natural (e.g., hurricanes and tsunamis) and human pressures on this environment require it to constantly adjust. More than any other area, the global coast has defined the progress of human culture and continues to be a singular influence in how humans connect to the …

Report I: An Assessment Of The Coastal And Marine Economies Of Massachusetts, University Of Massachusetts Donahue Institute, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

This three-part study — An Assessment of the Coastal and Marine Economies of Massachusetts — provides an analysis of the economic value of the coastal and marine economies as well as an overview of employment, wages, business activities and trends within important sectors of the Massachusetts marine economy. The data used is primarily from 2004, unless otherwise noted.

Enumerations Of The Kolmogorov Function, Richard Beigel, Harry Buhrman, Peter Fejer, Lance Fortnow, Piotr Grabowski, Luc Longpré, Andrej Muchnik, Frank Stephan, Leen Torenvliet

Computer Science Faculty Publication Series

A recursive enumerator for a function h is an algorithm f which enumerates for an input x finitely many elements including h(x). f is a k(n)-enumerator if for every input x of length n, h(x) is among the first k(n) elements enumerated by f. If there is a k(n)-enumerator for h then h is called k(n)-enumerable. We also consider enumerators which are only A-recursive for some oracle A.

We determine exactly how hard it is to enumerate the Kolmogorov function, which assigns to each string x its Kolmogorov complexity:

• For every underlying universal machine U, there is a constant a …