9,864 research outputs found
An investigation of correlation between pilot scanning behavior and workload using stepwise regression analysis
An electro-optical device called an oculometer which tracks a subject's lookpoint as a time function has been used to collect data in a real-time simulation study of instrument landing system (ILS) approaches. The data describing the scanning behavior of a pilot during the instrument approaches have been analyzed by use of a stepwise regression analysis technique. A statistically significant correlation between pilot workload, as indicated by pilot ratings, and scanning behavior has been established. In addition, it was demonstrated that parameters derived from the scanning behavior data can be combined in a mathematical equation to provide a good representation of pilot workload
Nematode control in 'green' ruminant production systems
Collectively, nematode parasites of domestic ruminants continue to pose the greatest disease problem in grazing livestock systems worldwide, despite the powerful and extensive chemotherapeutic arsenal available for their control. The widespread development of anthelmintic resistance, particularly in nematode parasites of small ruminants, and the trend towards nonchemical (ecological, organic, green) farming of livestock has provided an impetus for the research and development of alternative parasite control methods. This article provides a brief overview of the non-chemotherapeutic
options for parasite control and how they might
play a role either in organic farming or in other low-input
farming systems
Which program for whom? Evidence on the comparative effectiveness of public sponsored training programs in Germany
We use a new and exceptionally rich administrative data set for Germany to evaluate the employment effects of a variety of public sponsored training programs in the early 2000s. Building on the work of Sianesi (2003, 2004), we employ propensity score matching methods in a dynamic, multiple treatment framework in order to address program heterogeneity and dynamic selection into programs. Our results suggest that in West Germany both short-term and medium-term programs show considerable employment effects for certain population subgroups but in some cases the effects are zero in the medium run. Short-term programs are surprisingly effective when compared to the traditional and more expensive longer-term programs. With a few exceptions, we find little evidence for significant positive treatment effects in East Germany. There is some evidence that the employment effects decline for older workers and for low-skilled workers
Investigation of Mechanical Properties of Cryogenically Treated Music Wire
It has been reported that treating music wire (high carbon steel wire) by
cooling to cryogenic temperatures can enhance its mechanical properties with
particular reference to those properties important for musical performance. We
use such wire for suspending many of the optics in Advanced LIGO, the upgrade
to LIGO - the Laser Interferometric Gravitational-Wave Observatory. Two
properties that particularly interest us are mechanical loss and breaking
strength. A decrease in mechanical loss would directly reduce the thermal noise
associated with the suspension, thus enhancing the noise performance of mirror
suspensions within the detector. An increase in strength could allow thinner
wire to be safely used, which would enhance the dilution factor of the
suspension, again leading to lower suspension thermal noise. In this article we
describe the results of an investigation into some of the mechanical properties
of music wire, comparing untreated wire with the same wire which has been
cryogenically treated. For the samples we studied we conclude that there is no
significant difference in the properties of interest for application in
gravitational wave detectors
Users guide: The LaRC human-operator-simulator-based pilot model
A Human Operator Simulator (HOS) based pilot model has been developed for use at NASA LaRC for analysis of flight management problems. The model is currently configured to simulate piloted flight of an advanced transport airplane. The generic HOS operator and machine model was originally developed under U.S. Navy sponsorship by Analytics, Inc. and through a contract with LaRC was configured to represent a pilot flying a transport airplane. A version of the HOS program runs in batch mode on LaRC's (60-bit-word) central computer system. This document provides a guide for using the program and describes in some detail the assortment of files used during its operation
A small molecule that induces assembly of a four way DNA junction at low temperature
Small molecules that induce the formation of higher order DNA structures have potential therapeutic and nanotechnology applications. Screening of a click library has identified the first compound to induce the formation of a Holliday junction structure at room temperature without the need for a high temperature annealing step
Maintenance of Residential Rental Property: An Empirical Analysis
The maintenance costs of 137 residential rental properties in northwestern South Carolina are analyzed. The results show that maintenance cost per square foot increases with property age, tenant turnover, certain amenities, and for higher-rent properties. Compared to other property types, apartments exhibit higher maintenance costs per square foot with larger complexes showing lower per square foot maintenance costs than smaller complexes. This cost economy suggests added value to rental housing for larger complexes. Owners of multiple properties are found to pay higher maintenance costs. Finally, there is no observed relationship between absentee ownership and the level of property maintenance.
First report of Laternula elliptica in the Antarctic intertidal zone
Many Antarctic marine invertebrates are considered to be highly stenothermal, subjected to loss of functionality at increased temperatures and so at high risk of mortality in a rapidly warming environment. The bivalve Laternula elliptica is often used as a model taxon to test these theories. Here, we report the first instance L. elliptica from an intertidal site. Genetic analysis of the tissue confirms the species identity. A total of seven animals ranging in length from 6 to 85 mm were collected from 3 × 0.25 m2 quadrats of intertidal sediments at St Martha Cove on James Ross Island, Eastern Antarctic Peninsula. Ambient temperatures of 7.5 °C within the sediment and 10 °C (air) were recorded. This raises questions as to the current perception that “many Antarctic marine invertebrates cannot adapt to higher temperatures”
ASTM Committee D20 on Plastics Liaison Report
A viewgraph presentation describing plastic activities from committee D-20 is shown
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