Characterization of digital-micromirror device-based infrared scene projector

A test procedure is developed for an infrared laser scene projector, and applied to a projection system that we develop based on digital micromirror technology. The intended use will be for simulation and target training. Resolution and noise are significant parameters for target perception models of infrared imaging systems. System resolution is normally measured as the modulation transfer function (MTF), and its noise modeled through an appropriate signal standard deviation metric. We compare MTF measurements for both mid-wave (MWIR) and longwave IR (LWIR) bands for an infrared laser scene projector based on the digital micromirror device (DMD). Moreover, we use two complimentary models to characterize imaging camera noise. This provides a quantitative image-quality criterion of system performance

Ancient, independent evolution and distinct molecular features of the novel human T-lymphotropic virus type 4

<p>Abstract</p> <p>Background</p> <p>Human T-lymphotropic virus type 4 (HTLV-4) is a new deltaretrovirus recently identified in a primate hunter in Cameroon. Limited sequence analysis previously showed that HTLV-4 may be distinct from HTLV-1, HTLV-2, and HTLV-3, and their simian counterparts, STLV-1, STLV-2, and STLV-3, respectively. Analysis of full-length genomes can provide basic information on the evolutionary history and replication and pathogenic potential of new viruses.</p> <p>Results</p> <p>We report here the first complete HTLV-4 sequence obtained by PCR-based genome walking using uncultured peripheral blood lymphocyte DNA from an HTLV-4-infected person. The HTLV-4(1863LE) genome is 8791-bp long and is equidistant from HTLV-1, HTLV-2, and HTLV-3 sharing only 62–71% nucleotide identity. HTLV-4 has a prototypic genomic structure with all enzymatic, regulatory, and structural proteins preserved. Like STLV-2, STLV-3, and HTLV-3, HTLV-4 is missing a third 21-bp transcription element found in the long terminal repeats of HTLV-1 and HTLV-2 but instead contains unique c-Myb and pre B-cell leukemic transcription factor binding sites. Like HTLV-2, the PDZ motif important for cellular signal transduction and transformation in HTLV-1 and HTLV-3 is missing in the C-terminus of the HTLV-4 Tax protein. A basic leucine zipper (b-ZIP) region located in the antisense strand of HTLV-1 and believed to play a role in viral replication and oncogenesis, was also found in the complementary strand of HTLV-4. Detailed phylogenetic analysis shows that HTLV-4 is clearly a monophyletic viral group. Dating using a relaxed molecular clock inferred that the most recent common ancestor of HTLV-4 and HTLV-2/STLV-2 occurred 49,800 to 378,000 years ago making this the oldest known PTLV lineage. Interestingly, this period coincides with the emergence of <it>Homo sapiens sapiens </it>during the Middle Pleistocene suggesting that early humans may have been susceptible hosts for the ancestral HTLV-4.</p> <p>Conclusion</p> <p>The inferred ancient origin of HTLV-4 coinciding with the appearance of <it>Homo sapiens</it>, the propensity of STLVs to cross-species into humans, the fact that HTLV-1 and -2 spread globally following migrations of ancient populations, all suggest that HTLV-4 may be prevalent. Expanded surveillance and clinical studies are needed to better define the epidemiology and public health importance of HTLV-4 infection.</p

The Theory of Two-Currency Gambles

This paper describes a theory of decision making under uncertainty when payoffs are made in two different currencies. It is shown that immediate lotteries can be evaluated consistently using utility functions assessed in either currency. Delayed lotteries subject to the exchange risk may also be evaluated by single currency utility functions; the implications of the use of such functions are discussed. The conditions where a utility function should include the rate of exchange itself are outlined. Finally, the fallacy of the use of risk adjusted exchange rates for specific exchange management operations is discussed.

Liquid Crystal On Silicon Infrared Scene Projectors

As the deployment of IR sensors increases in the military arena, so does the need for testing, calibration and training in realistic infrared environments. This paper introduces liquid crystal on silicon (LCOS) technology and discusses key elements required to successfully transition these displays to the infrared. The resulting devices are not only appropriate for infrared scene projectors, but can also be used as infrared adaptive optics or non-mechanical beamsteering elements

The Use of Discriminant Analysis in Forecasting Exchange Rate Movements

This paper presents the results of an exploratory survey of the applicability of discriminant analysis to the determination of the medium-term (two-year) exchange rate changes. Using a discriminant function developed on observations drawn from 1961–1964 and 1965–1968, the authors have correctly predicted the devaluation or nondevaluation of 86 percent of the countries tested for the period 1971–1972. These results indicate predictive power at the .001 level of significance. A reduction of 36 percent in classification error is achieved by the method.© 1975 JIBS. Journal of International Business Studies (1975) 6, 33–50

Refractive Index At Thz Frequencies Of Various Plastics

We measure the refractive index via a minimum deviation prism technique of various plastics from 70-290μm (1-4THz) using a tunable terahertz gas laser. We find these plastics have indices varying from 1.43-1.61 over this range. © 2007 Optical Society of America