113,403 research outputs found
Creating Stronger Diversity Initiatives in Employment Settings
This article explores the common problems associated with ineffective diversity initiatives and what steps a firm can take to cultivate a successful plan. Diversity dilemmas in the workplace have long frustrated advocates who desire not only to see greater representation of minorities and women in firms, but also that those people are integrated across the firm and accepted as valued, productive members, of the firm’s culture. Knowing how an initiative fails to achieve diversity goals and learning from successful examples will enable firms to create a better work environment, capitalize on market opportunities, and enjoy many other benefits
Inflatable habitation for the lunar base
Inflatable structures have a number of advantages over rigid modules in providing habitation at a lunar base. Some of these advantages are packaging efficiency, convenience of expansion, flexibility, and psychological benefit to the inhabitants. The relatively small, rigid cylinders fitted to the payload compartment of a launch vehicle are not as efficient volumetrically as a collapsible structure that fits into the same space when packaged, but when deployed is much larger. Pressurized volume is a valuable resource. By providing that resource efficiently, in large units, labor intensive external expansion (such as adding additional modules to the existing base) can be minimized. The expansive interior in an inflatable would facilitate rearrangement of the interior to suite the evolving needs of the base. This large, continuous volume would also relieve claustrophobia, enhancing habitability and improving morale. The purpose of this paper is to explore some of the aspects of inflatable habitat design, including structural, architectural, and environmental considerations. As a specific case, the conceptual design of an inflatable lunar habitat, developed for the Lunar Base Systems Study at the Johnson Space Center, is described
Modelling repeated epidemics with general infection kernels
An integral equation approach is taken to explore the characteristics of
a general infectious disease in a homogeneous population. It is shown that
the final size of the epidemic depends on the basic reproduction ratio for
the infection and the initial number of susceptibles. A discrete map for the
susceptible population from epidemic generation to epidemic generation is
formed to consider the long term behaviour of the disease in a population of
constant size
Video Evidence That London Infants Can Resettle Themselves Back to Sleep After Waking in the Night, as well as Sleep for Long Periods, by 3 Months of Age
Objective: Most infants become settled at night by 3 months of age, whereas infants not settled by 5 months are likely to have long-term sleep-waking problems. We assessed whether normal infant development in the first 3 months involves increasing sleep-period length or the ability to resettle autonomously after waking in the night. Methods: One hundred one infants were assessed at 5 weeks and 3 months of age using nighttime infrared video recordings and parental questionnaires. Results: The clearest development was in sleep length; 45% of infants slept continuously for 5 hours or more at night at 3 months compared with 10% at 5 weeks. In addition, around a quarter of infants woke and resettled themselves back to sleep in the night at each age. Autonomous resettling at 5 weeks predicted prolonged sleeping at 3 months suggesting it may be a developmental precursor. Infants reported by parents to sleep for a period of 5 hours or more included infants who resettled themselves and those with long sleeps. Three-month olds fed solely breast milk were as likely to self-resettle or have long sleep bouts as infants fed formula or mixed breast and formula milk. Conclusions: Infants are capable of resettling themselves back to sleep in the first 3 months of age; both autonomous resettling and prolonged sleeping are involved in “sleeping through the night” at an early age. Findings indicate the need for physiological studies of how arousal, waking, and resettling develop into sustained sleeping and of how environmental factors support these endogenous and behavioral processes
Ghosts of Critical Gravity
Recently proposed "critical" higher-derivative gravities in are
expected to carry logarithmic representation of the Anti de Sitter isometry
group. In this note, we quantize linear fluctuations of these critical
gravities, which are known to be either identical with linear fluctuations of
Einstein's gravity or else satisfy logarithmic boundary conditions at spacial
infinity. We identify the scalar product uniquely defined by the symplectic
structure implied by the classical action, and show that it does not posses
null vectors. Instead, we show that the scalar product between any two Einstein
modes vanishes, while the scalar product of an Einstein mode with a logarithmic
mode is generically nonzero. This is the basic property of logarithmic
representation that makes them neither unitary nor unitarizable.Comment: v2: typos corrected and slight clarifications. 11 page
Precision measurement noise asymmetry and its annual modulation as a dark matter signature
Dark matter may be composed of ultralight quantum fields that form
macroscopic objects. As the Earth moves through the galaxy, interactions with
such objects may leave transient signatures in terrestrial experiments. These
signatures may be sought by analyzing correlations between multiple devices in
a distributed network. However, if the objects are small (<~10^3 km) it becomes
unlikely that more than one device will be affected in a given event. Such
models may, however, induce an observable asymmetry in the noise distributions
of precision measurement devices, such as atomic clocks. Further, an annual
modulation in this asymmetry is expected. Such an analysis may be performed
very simply using existing data, and would be sensitive to models with a high
event rate, even if individual events cannot be resolved. For certain models,
our technique extends the discovery reach beyond that of existing experiments
by many orders of magnitude
Component specific modeling
Modern jet engine design imposes extremely high loadings and temperatures on hot section components. A series of interdisciplinary modeling and analysis techniques which were specialized to address three specific components (combustor burner linings, hollow air-cooled turbine blades, and air-cooled turbine vanes) were developed and verified. These techniques will incorporate data as well as theoretical methods from many diverse areas, including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. Building on the proven techniques already available in these fields, the new methods developed will be integrated to predict temperature, deformation, stress, and strain histories throughout a complete flight mission
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