1,847 research outputs found
The 13.9 GHz short pulse radar noise figure measurements utilizing silicon and gallium-arsenide mixer diodes
An analysis was made on two commercially available silicon and gallium arsenide Schottky barrier diodes. These diodes were selected because of their particularly low noise figure in the frequency range of interest. The specified noise figure for the silicon and gallium arsenide diodes were 6.3 db and 5.3 db respectively when functioning as mixers in the 13.6 GHz region with optimum local oscillator drive
Conductivity and the current-current correlation measure
We review various formulations of conductivity for one-particle Hamiltonians
and relate them to the current-current correlation measure. We prove that the
current-current correlation measure for random Schr\"odinger operators has a
density at coincident energies provided the energy lies in a localization
regime. The density vanishes at such energies and an upper bound on the rate of
vanishing is computed. We also relate the current-current correlation measure
to the localization length
The Development and Implementation of an Employee Education Session and Self-Checklist Teaching Face Mask Compliance to Cafeteria Workers at a University in the Midwest
The COVID-19 pandemic has contributed to the need for public health education. The enforcement of the statewide face mask mandate required the public to make a rapid behavior change. The face mask mandate also required higher education institutions to develop and implement evidence-based education modules to help decrease the risk of COVID-19 transmission. University cafeteria workers were required to wear masks while preparing and serving food.
The project takes place within a cafeteria at a local university in the Midwest during the beginning phases of the statewide face mask mandate. The population of focus includes 14 cafeteria workers responsible for food preparation and serving. University cafeteria workers experience frequent encounters with faculty, students, and visitors.
Observations included face mask noncompliance among 8 out of 10 cafeteria workers. Mask shifting often occurs with movement while performing required tasks. Improper mask compliance leads to an increased risk of COVID-19 transmission (Centers for Disease Control and Prevention, 2020a). The identified knowledge deficit among the participants correlated with the need for quality improvement and education. The project\u27s goals included developing a sustainable education module with a self-checklist and promoting a behavior change (Figure 2).
Before the conduction of the employee education module, each participant completed and submitted a pre-education survey (Appendix A). The self-checklist provides the fundamental steps necessary to ensure proper face mask utilization. The employees received the instruction to conduct a self-checklist hourly during each shift throughout the 10-day implementation phase. After the completion of the education session, management displayed the self-checklist visual at eight high-traffic locations. The participants began to utilize the checklist every hour or as needed. The cafeteria manager conducted surveillance and observation throughout the 10 days. On the 11th day, the participants completed and submitted a post-intervention survey (Appendix B) before the education module review session. Throughout this time, participants had the opportunity to verbalize feedback.
A post-intervention survey revealed that 12 of the 14 participants (93%) would continue to utilize the self-checklist. Surveillance conducted through management and self-assessment surveys revealed an overall improvement in the frequency of the continuous and proper utilization of facial masks, including the core concepts of covering the nose, mouth, and chin while simultaneously wearing the mask snuggly against the face. Additionally, participants reported an increased level of comfort while wearing face masks.
The project outcomes and goals indicate an overall increase in engagement, knowledge, and face mask compliance. The recommendation includes expanding the Check Yourself education module to form a public health initiative. The project expansion will include a free face mask drive and diversified versions of multimedia education, including commercial, video, and social media platforms to promote sustainability
Measurements of the effect of horizontal variability of atmospheric backscatter on dial measurements
The horizontal variability of atmospheric backscatter may have a substantial effect on how Differential Absorption Lidar (DIAL) data must be taken and analyzed. To minimize errors, lidar pulse pairs are taken with time separations which are short compared to the time scales associated with variations in atmospheric backscatter. To assess the atmospheric variability for time scales which are long compared to the lidar pulse repetition rate, the variance of the lidar return signal in a given channel can be computed. The variances of the on-line, off-line, and ration of the on-line to off-line signals at given altitudes obtained with the dual solid-state Alexandrite laser system were calculated. These evaluations were made for both down-looking aircraft and up-looking ground-based lidar data. Data were taken with 200 microsecond separation between on-line and off-line laser pulses, 30 m altitude resolution, 5 Hz repetition rate, and the signal were normalized for outgoing laser energy
Real-time atmospheric absorption spectra for in-flight tuning of an airborne dial system
Real-time measurements of atmospheric absorption spectra are displayed and used to precisely calibrate and fix the frequency of an Alexandrite laser to specific oxygen absorption features for airborne Differential Absorption Lidar (DIAL) measurements of atmospheric pressure and temperature. The DIAL system used contains two narrowband tunable Alexandrite lasers: one is electronically scanned to tune to oxygen absorption features for on-line signals while the second is used to obtain off-line (nonabsorbed) atmospheric return signals. The lidar operator may select the number of shots to be averaged, the altitude, and altitude interval over which the signals are averaged using single key stroke commands. The operator also determines exactly which oxygen absorption lines are scanned by comparing the line spacings and relative strengths with known line parameters, thus calibrating the laser wavelength readout. The system was used successfully to measure the atmospheric pressure profile on the first flights of this lidar, November 20, and December 9, 1985, aboard the NASA Wallops Electra aircraft
Airborne Lidar measurements of the atmospheric pressure profile with tunable Alexandrite lasers
The first remote measurements of the atmospheric pressure profile made from an airborne platform are described. The measurements utilize a differential absorption lidar and tunable solid state Alexandrite lasers. The pressure measurement technique uses a high resolution oxygen A band where the absorption is highly pressure sensitive due to collision broadening. Absorption troughs and regions of minimum absorption were used between pairs of stongly absorption lines for these measurements. The trough technique allows the measurement to be greatly desensitized to the effects of laser frequency instabilities. The lidar system was set up to measure pressure with the on-line laser tuned to the absorption trough at 13147.3/cm and with the reference laser tuned to a nonabsorbing frequency near 13170.0/cm. The lidar signal returns were sampled with a 200 range gate (30 vertical resoltion) and averaged over 100 shots
Thermal microwave emissions from vegetated fields: A comparison between theory and experiment
The radiometric measurements over bare field and fields covered with grass, soybean, corn, and alfalfa were made with 1.4 GHz and 5 GHz microwave radiometers during August - October 1978. The measured results are compared with radiative transfer theory treating the vegetated fields as a two layer random medium. It is found that the presence of a vegetation cover generally gives a higher brightness temperature T(B) than that expected from a bare soil. The amount of this T(B) excess increases in the vegetation biomass and in the frequency of the observed radiation. The results of radiative transfer calculations generally match well with the experimental data, however, a detailed analysis also strongly suggests the need of incorporating soil surface roughness effect into the radiative transfer theory in order to better interpret the experimental data
GSFC short pulse radar, JONSWAP-75
In September 1975, the Goddard Space Flight Center operated a short pulse radar during ocean wave measuring experiments off the coast of West Germany in the North Sea. The experiment was part of JONSWAP-75. The radar system and operations during the experiment are described along with examples of data
SOCI430B: Perspectives on Global Citizenship Syllabus 2011-2012
This document details the goals and objectives, curriculum design, structure, and presentation of Perspectives on Global Citizenship – an interdisciplinary and interactive online course. The course was designed to complement students’ specialized areas of learning, and to challenge students to consider what responsibility they have – within their political, social, cultural and professional contexts – to participate as active global citizens. It comprises twelve weekly thematic modules, on a Blackboard Vista course management platform, and makes use of Vista communication and collaboration tools. Themes include: • Ethics of Global Citizenship • What is citizenship? • The Challenge of Global Divisions: Race, Ethnicity, Nation, State • Challenging Old Conceptions of Citizenship: Diversity and Multiculturalism • The Challenge of Being Informed: Media, Communications and Critical Thinking • Poverty • Requirements for a Healthy Society • Consumerism and Consumer Choices • Human Impact on the Environment • Sustainability • Global Citizenship in Action Students participate in weekly topical discussions with peers from different disciplines and institutions, and complete four short written assignments over the course of the semester. Assessment is continuous, of both discussion contributions and written work
Rat Cardiovascular Responses to Whole Body Suspension: Head-down and Non-Head-Down Tilt
The rat whole body suspension technique mimics responses seen during exposure to microgravity and was evaluated as a model for cardiovascular responses with two series of experiments. In one series, changes were monitored in chronically catheterized rats during 7 days of Head-Down Tilt (HDT) or Non-Head-Down Tilt (N-HDT) and after several hours of recovery. Elevations of mean arterial (MAP), systolic, and diastolic pressures of approx. 20 % (P less than 0.05) in HDT rats began as early as day 1 and were maintained for the duration of suspension. Pulse pressures were relatively unaffected, but heart rates were elevated approx. 10 %. During postsuspension (2-7 h), most cardiovascular parameters returned to presuspension levels. N-HDT rats exhibited elevations chiefly on days 3 and 7. In the second series, blood pressure was monitored in 1- and 3-day HDT and N-HDT rats to evaluate responses to rapid head-up tilt. MAP, systolic and diastolic pressures, and HR were elevated (P less than 0.05) in HDT and N-HDT rats during head-up tilt after 1 day of suspension, while pulse pressures remained un changed. HDT rats exhibited elevated pretilt MAP and failed to respond to rapid head-up tilt with further increase of MAP on day 3, indicating some degree of deconditioning. The whole body suspended rat may be useful as a model to better understand responses of rats exposed to microgravity
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