The Commercial Application of Missile/Space Technology, Parts 1 and 2

This report is concerned with the transfer of technology from missile and space programs to non-missile/space applications in the United States. It presents the findings of a University of Denver Research Institute study sponsored by a National Aeronautics and Space Administration (NASA) grant awarded in November 1961. Initial stimulation for the unsolicited proposal leading to this study came from a 1960 Brookings Institution report to NASA, Proposed Studies on the Implications of Peaceful Space Activities for Human Affairs

Comparing choice models of river health improvement for the Goulburn River

The extent of the benefits of improved river health remain uncertain. Quantifying these benefits is useful in prioritising policy investments. This study uses the Choice Modelling technique to estimate the value that households attach to attributes of improved river health. Data from a choice modelling survey supported by DSE Victoria are employed to elicit household preferences in a case study of the Goulburn River. Results from conditional and nested logit model specifications indicate that respondents hold positive values for higher levels of fish and bird populations and for increasing riverside vegetation. The standard Hausman test for Independence-from-Irrelevant-Alternatives (IIA) assumptions violations is found to give inconsistent results. The value estimates of the conditional and nested logit models are shown to be statistically similar indicating that testing for IIA violation may be more complicated than currently assumed thus raising questions about the efficacy of the more complex nested logit model.Cheap talk, choice modelling, Mekong River Delta, wetland values, willingness to pay, Resource /Energy Economics and Policy, Q25,

Laser-Induced Thermal Acoustics Theory and Expected Experimental Errors when Applied to a Scramjet Isolator Model

A scramjet isolator model test apparatus is being assembled in the Isolator Dynamics Research Lab (IDRL) at the NASA Langley Research Center in Hampton, Virginia. The test apparatus is designed to support multiple measurement techniques for investigating the flow field in a scramjet isolator model. The test section is 1-inch high by 2-inch wide by 24-inch long and simulates a scramjet isolator with an aspect ratio of two. Unheated, dry air at a constant stagnation pressure and temperature is delivered to the isolator test section through a Mach 2.5 planar nozzle. The isolator test section is mechanically back-pressured to contain the resulting shock train within the 24-inch isolator length and supports temperature, static pressure, and high frequency pressure measurements at the wall. Additionally, nonintrusive methods including laser-induced thermal acoustics (LITA), spontaneous Raman scattering, particle image velocimetry, and schlieren imaging are being incorporated to measure off-wall fluid dynamic, thermodynamic, and transport properties of the flow field. Interchangeable glass and metallic sidewalls and optical access appendages permit making multiple measurements simultaneously. The measurements will be used to calibrate computational fluid dynamics turbulence models and characterize the back-pressured flow of a scramjet isolator. This paper describes the test apparatus, including the optical access appendages; the physics of the LITA method; and estimates of LITA measurement uncertainty for measurements of the speed of sound and temperature

On the viability of Escherichia coli cells lacking DNA topoisomerase I

Copyright @ 2012 Stockum et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is made available through the Brunel Open Access Publishing Fund.Background: Manipulations of the DNA double helix during replication, transcription and other nucleic acid processing cause a change of DNA topology, which results in torsional stress. This stress is relaxed by DNA topoisomerases, a class of enzymes present in all domains of life. Negatively supercoiled DNA is relaxed by type IA topoisomerases that are widespread in bacteria, archaea and eukaryotes. In Escherichia coli there is conflicting data about viability of ΔtopA cells lacking topoisomerase I. Results: In this study we sought to clarify whether E. coli cells lacking topoisomerase I are viable by using a plasmid-based lethality assay that allowed us to investigate the phenotype of ΔtopA cells without the presence of any compensatory mutations. Our results show that cells lacking topoisomerase I show an extreme growth defect and cannot be cultured without the accumulation of compensatory mutations. This growth defect can be partially suppressed by overexpression of topoisomerase III, the other type IA topoisomerase in E. coli, suggesting that the accumulation of torsional stress is, at least partially, responsible for the lethality of ΔtopA cells. The absence of RNase HI strongly exacerbates the phenotype of cells lacking topoisomerase I, which supports the idea that the processing of RNA:DNA hybrids is vitally important in ΔtopA cells. However, we did not observe suppression of the ΔtopA phenotype by increasing the level of R-loop processing enzymes, such as RNase HI or RecG. Conclusions: Our data show unambiguously that E. coli cells are not viable in the absence of DNA topoisomerase I without the presence of compensatory mutations. Furthermore, our data suggest that the accumulation of R-loops is not the primary reason for the severe growth defect of cells lacking topoisomerase I, which is in contrast to the current literature. Potential reasons for this discrepancy are discussed.The Medical Research Council (grant G0800970) and The Leverhulme Trust

Laser-Induced Thermal Acoustic Measurements in a Highly Back-Pressured Scramjet Isolator Model: A Research Plan

Under the Propulsion Discipline of NASA s Fundamental Aeronautics Program s Hypersonics Project, a test apparatus, for testing a scramjet isolator model, is being constructed at NASA's Langley Research Center. The test apparatus will incorporate a 1-inch by 2-inch by 15-inch-long scramjet isolator model supplied with 2.1 lbm/sec of unheated dry air through a Mach 2.5 converging-diverging nozzle. The planned research will incorporate progressively more challenging measurement techniques to characterize the flow field within the isolator, concluding with the application of the Laser-Induced Thermal Acoustic (LITA) measurement technique. The primary goal of this research is to use the data acquired to validate Computational Fluid Dynamics (CFD) models employed to characterize the complex flow field of a scramjet isolator. This paper describes the test apparatus being constructed, pre-test CFD simulations, and the LITA measurement technique

A Middle Miocene Rhinoceros Quarry in Morrill County, Nebraska (with Notes on Hip Disease in Diceratherium)

Extensive deposits of fossil rhinoceros bones have been excavated from University of Nebraska State Museum collecting localities Mo-113, -114, -115, -116, and -118 some 8 1/2 to 9 1/2 miles north of Bridgeport, Morrill County, Nebraska. The fossils were associated with other faunal elements in the lower portion of the Marsland formation (middle Miocene) of the Hemingford group. The rhinoceros is considered to be Diceratherium niobrarensis Peterson, geologic variety. A pathologic right femur of D. niobrarensis provides evidence of hip disease in the medial Miocene rhinoceroses

A Middle Miocene Rhinoceros Quarry in Morrill County, Nebraska (with Notes on Hip Disease in Diceratherium)

Extensive deposits of fossil rhinoceros bones have been excavated from University of Nebraska State Museum collecting localities Mo-113, -114, -115, -116, and -118 some 8 1/2 to 9 1/2 miles north of Bridgeport, Morrill County, Nebraska. The fossils were associated with other faunal elements in the lower portion of the Marsland formation (middle Miocene) of the Hemingford group. The rhinoceros is considered to be Diceratherium niobrarensis Peterson, geologic variety. A pathologic right femur of D. niobrarensis provides evidence of hip disease in the medial Miocene rhinoceroses

The NASA Langley Isolator Dynamics Research Lab

The Isolator Dynamics Research Lab (IDRL) is under construction at the NASA Langley Research Center in Hampton, Virginia. A unique test apparatus is being fabricated to support both wall and in-stream measurements for investigating the internal flow of a dual-mode scramjet isolator model. The test section is 24 inches long with a 1-inch by 2-inch cross sectional area and is supplied with unheated, dry air through a Mach 2.5 converging-diverging nozzle. The test section is being fabricated with two sets (glass and metallic) of interchangeable sidewalls to support flow visualization and laser-based measurement techniques as well as static pressure, wall temperature, and high frequency pressure measurements. During 2010, a CFD code validation experiment will be conducted in the lab in support of NASA s Fundamental Aerodynamics Program. This paper describes the mechanical design of the Isolator Dynamics Research Lab test apparatus and presents a summary of the measurement techniques planned for investigating the internal flow field of a scramjet isolator model

Replication fork regression in vitro by the Werner syndrome protein (WRN): Holliday junction formation, the effect of leading arm structure and a potential role for WRN exonuclease activity

The premature aging and cancer-prone disease Werner syndrome stems from loss of WRN protein function. WRN deficiency causes replication abnormalities, sensitivity to certain genotoxic agents, genomic instability and early replicative senescence in primary fibroblasts. As a RecQ helicase family member, WRN is a DNA-dependent ATPase and unwinding enzyme, but also possesses strand annealing and exonuclease activities. RecQ helicases are postulated to participate in pathways responding to replication blockage, pathways possibly initiated by fork regression. In this study, a series of model replication fork substrates were used to examine the fork regression capability of WRN. Our results demonstrate that WRN catalyzes fork regression and Holliday junction formation. This process is an ATP-dependent reaction that is particularly efficient on forks containing single-stranded gaps of at least 11–13 nt on the leading arm at the fork junction. Importantly, WRN exonuclease activity, by digesting the leading daughter strand, enhances regression of forks with smaller gaps on the leading arm, thus creating an optimal structure for regression. Our results suggest that the multiple activities of WRN cooperate to promote replication fork regression. These findings, along with the established cellular consequences of WRN deficiency, strongly support a role for WRN in regression of blocked replication forks

Replication Fork Regression \u3cem\u3eIn Vitro\u3c/em\u3e by the Werner Syndrome Protein (WRN): Holliday Junction Formation, the Effect of Leading Arm Structure and a Potential Role for WRN Exonuclease Activity

The premature aging and cancer-prone disease Werner syndrome stems from loss of WRN protein function. WRN deficiency causes replication abnormalities, sensitivity to certain genotoxic agents, genomic instability and early replicative senescence in primary fibroblasts. As a RecQ helicase family member, WRN is a DNA-dependent ATPase and unwinding enzyme, but also possesses strand annealing and exonuclease activities. RecQ helicases are postulated to participate in pathways responding to replication blockage, pathways possibly initiated by fork regression. In this study, a series of model replication fork substrates were used to examine the fork regression capability of WRN. Our results demonstrate that WRN catalyzes fork regression and Holliday junction formation. This process is an ATP-dependent reaction that is particularly efficient on forks containing single-stranded gaps of at least 11–13 nt on the leading arm at the fork junction. Importantly, WRN exonuclease activity, by digesting the leading daughter strand, enhances regression of forks with smaller gaps on the leading arm, thus creating an optimal structure for regression. Our results suggest that the multiple activities of WRN cooperate to promote replication fork regression. These findings, along with the established cellular consequences of WRN deficiency, strongly support a role for WRN in regression of blocked replication forks