United States Department of the Army

About: United States Department of the Army is a government organization based out in Arlington, Virginia, United States. It is known for research contribution in the topics: Poison control & Population. The organization has 32668 authors who have published 42453 publications receiving 947075 citations. The organization is also known as: DA & U.S. Department of the Army.

Numerical simulations of the profile properties of undeformed first-year sea ice during the growth season

Abstract: A model is presented for estimating salinity profiles for the first-year sea ice during the growth season, in which ice growth equations were coupled with salt entrapment and brine drainage relations to obtain the relationship between the initial ice salinity and the ice-growth velocity and seawater salinity, as well as the subsequent drainage of brine from the ice. The results obtained were found to be in reasonable agreement with field observations in that they showed characteristic C-shaped profiles similar to natural profiles. The average ice salinity values were also in reasonable agreement with field data. The predicted ice property profiles give composite plate properties that are significantly different from bulk property estimates that would result by assuming that sea ice could be represented as a homogeneous plate.

Instructional conditions for using dynamic visual displays: a review

Abstract: A review of research related to the learning effect of dynamic versus static visual displays in media-based instruction is presented. The analysis reveals that the dynamic visual display (DVD) is generally more effective than the static visual display (SVD). However, the research findings do not consistently support the superior effect of DVDs. These conflicting findings seem to be related to the different theoretical rationales and methodological approaches used in various studies and suggest that the use of DVDs should be determined selectively. From the literature review and theoretical discussions about instructional functions of DVDs, we propose six instructional conditions under which DVDs can be effectively used. The conditions are for: (a) demonstrating sequential actions in a procedural task; (b) simulating causal models of complex system behaviors; (c) explicitly representing invisible system functions and behaviors; (d) illustrating a task which is difficult to describe verbally; (e) providing a visual analogy for an abstract and symbolic concept, and (f) obtaining attention focused on specific tasks or presentation displays. Finally, several important considerations for the design and presentation of DVDs are discussed.

Work Stress and Burnout Among Nurses: Role of the Work Environment and Working Conditions

Abstract: Stress and burnout are concepts that have sustained the interest of nurses and researchers for several decades. These concepts are highly relevant to the workforce in general and nursing in particular. Despite this interest and relevance, the effects of stress and burnout on patient outcomes, patient safety, and quality care are not well defined by evidence. In fact, the link between stress and burnout to patient outcomes has been explored in only four investigations. There is a great need for comprehensive studies that will examine these dynamics in a way that will yield more solid evidence on which to base practice.

Compact wideband microstrip antenna with leaky-wave excitation

Abstract: A compact wideband leaky-wave excitation microstrip antenna is provided by a group of microstrip patches disposed on a top region of a dielectric substrate stacked on a conductive ground plane. The top region of the dielectric substrate and the dielectric substrate can be composed of either the same or different dielectric materials. A means for feeding an RF signal, which can be a center feed pin, that normally touches the top conducting patch is electrically isolated from the radiating patches. This arrangement confines the feed current within the probe pin to give an increased input resistance. The compact wideband leaky-wave excitation microstrip antenna permits significant reductions in antenna size, resulting in microstrip antennas with a smaller surface area.