10,314 research outputs found
Optical instrument employing reticle having preselected visual response pattern formed thereon
An optical instrument for use in locating indicator lights or the like on a work surface is described. It comprises a tubular housing, a lens mounted within the housing and including an inner surface coated with a dichroic material that is capable of reflecting a portion of the light incident thereon, a plate mounted within the housing opposite the lens and having a central aperture, a transparent substrate disposed within the housing intermediate the lens and the plate, the substrate including a first surface disposed in a facing relationship to the dichroic material, and a reticle formed on the first surface and comprised of a material capable of reflecting light
Simulator scene display evaluation device
An apparatus for aligning and calibrating scene displays in an aircraft simulator has a base on which all of the instruments for the aligning and calibrating are mounted. Laser directs beam at double right prism which is attached to pivoting support on base. The pivot point of the prism is located at the design eye point (DEP) of simulator during the aligning and calibrating. The objective lens in the base is movable on a track to follow the laser beam at different angles within the field of vision at the DEP. An eyepiece and a precision diopter are movable into a position behind the prism during the scene evaluation. A photometer or illuminometer is pivotable about the pivot into and out of position behind the eyepiece
Cockpit Window Edge Proximity Effects on Judgements of Horizon Vertical Displacement
To quantify the influence of a spatially fixed edge on vertical displacement threshold, twenty-four males (12 pilots, 12 non-pilots) were presented a series of forced choice, paired comparison trials in which a 32 deg arc wide, thin, luminous horizontal stimulus line moved smoothly downward through five angles from a common starting position within a three second-long period. The five angles were 1.4, 1.7, 2, 2.3, and 2.6 deg. Each angle was presented paired with itself and the other four angles in all combinations in random order. For each pair of trials the observer had to choose which trial possessed the largest displacement. A confidence response also was made. The independent variable was the angular separation between the lower edge of a stable 'window' aperture through which the stimulus was seen to move and the lowest position attained by the stimulus. It was found that vertical displacement accuracy is inversely related to the angle separating the stimulus and the fixed window edge (p = .05). In addition, there is a strong tendency for pilot confidence to be lower than that of non-pilots for each of the three angular separations. These results are discussed in erms of selected cockpit features and as they relate to how pilots judge changes in aircraft pitch attitude
The Use of Historical Census Data for Mortality and Fertility Research
This paper illustrates the application of indirect techniques of fertility and mortality estimation to historical census data, both in published form and as micro census samples derived from the original enumerators' manuscripts. There are many instances in which census data exist but adequate vital registration data do not, such as in the United States prior to 1933, when the Birth and Death Registration Areas finally covered the entire nation. Since the United States has taken decennial censuses since 1790, and since all the original population schedules except those for 1890 have been preserved, it is possible to apply these indirect methods. For example, the censuses of 1900 and 1910 asked questions on children ever born, children surviving, and duration of current marriage, but this information was never tabulated or used for 1900 and only partly tabulated for 1910. The Public Use Samples of the 1900 and 1910 censuses make possible the utilization of those data to estimate levels, differentials, and even recent trends in childhood mortality. Application of own-children methods to samples of the censuses since 1850 permits estimation of age-specific overall and marital fertility rates. Finally, the use of the 1900 Public Use Sample in conjunction with published data on parity from the 1910 census (or tabulations from the 1910 Public Use Sample) allows application of the two-census, parity increment method of birth rate estimation.
Health, Height, Nutrition, and Mortality: Evidence on the "Antebellum Puzzle" from Union Army Recruits in the Middle of the Nineteenth Century
The Antebellum Puzzle' describes the situation of declining stature and pos mortality in the three decades prior to the American Civil War (1861-65). It is this period was one of rapid economic growth and development in the United State the debate has centered on whether the American diet, both in terms of protein a deteriorated in the middle of the 19th century. But the mortality environment a have worsened (or at least did not improve), connected with factors such as urba commercialization, and increased geographic mobility. This paper uses data on t Union Army recruits as an indicator of the standard of living of Americans durin Particular attention is paid to New York State and comparisons to the rest of th York State, mortality was not improving in the antebellum period and was deterio York City. For the United States and for New York State, urbanization was negat heights, as was the census death rate in 1850 and a measure of mobility (proport population foreign born). Although, New York State's agriculture was rapidly co in this era and specializing in dairy products, its nutrition may have been dete with substantial local variation. Mortality was also not improving and worsened Both contributed to a decline in this biological indicator of the standard of li both New York and the whole United States were experiencing Smithian' economic g (induced by transport improvements and widening markets) with negative externali York State was an area in advance of much of the nation in terms of both urban/i agricultural development in the antebellum period.
Ethnic Differences in Demographic Behavior in the United States: Has There Been Convergence?
This paper looks at the fertility, mortality, and marriage experience of racial, ethnic, and nativity groups in the United States from the 19th to the late 20th centuries. The first part consist of a description and critique of the racial and ethnic categories used in the federal census and in the published vital statistics. The second part looks at these three dimensions of demographic behavior. There has been both absolute and relative convergence of fertility across groups, It has been of relatively recent origin and has been due, in large part, to stable, or even slightly increasing, birth rates for the majority white population combined with declining birth rates for blacks and the Asian-origin, Hispanic-origin, and Amerindian populations. This has not been true for mortality. The black population has experienced absolute convergence but relative deterioration in mortality (neonatal and infant mortality, maternal mortality, expectation of life at birth, and age-adjusted death rates), in contrast to the Amerindian and Asian-origin populations. The Asian-origin population actually now has age-adjusted death rates significantly lower than those for the white population. The disadvantaged condition of the black population and the deteriorating social safety net are the likely origins of this outcome. Finally, there was a trend toward earlier and more extensive marriage from about 1900 up to the 1960s. At this point, coincident with the end of the 'Baby Boom,' there has been a movement to later marriage for both males and females among whites, blacks, and the Hispanic-origin populations. This trend has been more extreme in the black population, especially among females. There has also been a significant rise in proportions never-married at ages 45-54 among blacks and, to a lesser extent, among Hispanics. So here too, there has been some divergence.
The Urban Mortality Transition in the United States, 1800-1940
In the United States in the 19th and early 20th centuries, there was a substantial mortality 'penalty' to living in urban places. This circumstance was shared with other nations. By around 1940, this penalty had been largely eliminated, and it was healthier, in many cases, to reside in the city than in the countryside. Despite the lack of systematic national data before 1933, it is possible to describe the phenomenon of the urban mortality transition. Early in the 19th century, the United States was not particularly urban (only 6.1% in 1800), a circumstance which led to a relatively favorable mortality situation. A national crude death rate of 20-25 per thousand per year would have been likely. Some early data indicate that mortality was substantially higher in cities, was higher in larger relative to smaller cities, and was higher in the South relative to the North. By 1900, the nation had become about 40% urban (and 56% by 1940). It appears that death rates, especially in urban areas, actually rose (or at least did not decline) over the middle of the 19th century. Increased urbanization, as well as developments in transport and commercialization and increased movements of people into and throughout the nation, contributed to this. Rapid urban growth and an inadequate scientific understanding of disease processes contributed to the mortality crisis of the early and middle nineteenth century in American cities. The sustained mortality transition only began about the 1870s. Thereafter the decline of urban mortality proceeded faster than in rural places, assisted by significant public works improvements and advances in public health and eventually medical science. Much of the process had been completed by the 1940s. The urban penalty had been largely eliminated and mortality continued to decline despite the continued growth in the urban share of the population.
Preliminary study of head-up assessment techniques. 1: Viewing duration of instrument panel and HUD symbology using a recall methodology
Eight commercial pilots were shown 50 colored, high fidelity slides of a standard instrument panel (IP) with the needle positions of each instrument varying from slide to slide and then 50 slides of a head-up display (HUD) symbology format which contained an equivalent amount of flight-related information as the instrument panel slides. All stimuli were presented under controlled, static viewing conditions that allowed the measurement of the speed and accuracy with which one randomly selected flight parameter on each slide could be read. The subject did not know which parameter would be requested and, therefore, had to remember the total set of information in order to answer the question correctly. The results showed that from 6.6 - 8.7 sec total viewing time was required to correctly extract altitude, airspeed, heading, VSI, or ADI from the IP slides and from 6.1 to 7.4 sec for the HUD slides
Project plan for joint FAA/NASA head-up display concept evaluation
Head-Up Display (HUD) concept for large commercial turbojet transport aircraft is considered for the its contribution to aviation safety in the form of improved performance during the approach and landing phase flight. The basic reearch areas represent fundamental questions that are still unresolved and which were considered important to the effective use of the HUD by pilots. Project documentation and management responsibilities are outlined
Changes in perceived size and shape of a highly luminous target
Perceived changes in size and shape of highly luminous target and relation to associated stimul
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