Spatial frequency response of an optical heterodyne receiver

The principles of transfer function analysis are applied to a passive optical heterodyne receiver to obtain the modulation transfer function (MTF). MTF calculations are performed based on an optical platform which is imaging vertically varying profiles at worst case shuttle orbit altitudes. An analysis of the derogatory effects of sampling (aliasing) and central obscurations on both resolution and heterodyne efficiency is given. It is found that the cascading property of MTF analysis must be carefully applied since the coherent transfer function of the optical receiver and that due to the local oscillator-detector combination are not separable but are related by the convolution of their products. Application of these results to the specific case of a space-lab type optical heterodyne receiver shows that resolutions of the order of 1.5-2.0 Km are possible for worst-case type orbital scenarios. Further, comparison of obscured-type receivers (e.g., Cassegrains) with unobscured receivers shows that both resolution and efficiency are severely degraded in an obscured-type receiver and consequently should not be used for a passive heterodyne detection scheme

Wavelength error analysis in a multiple-beam Fizeau laser wavemeter having a linear diode array readout

An estimate of the wavelength accuracy of a laser wavemeter is performed for a system consisting of a multiple-beam Fizeau interferometer and a linear photosensor array readout. The analysis consists of determining the fringe position errors which result when various noise sources are included in the fringe forming and detection process. Two methods of estimating the fringe centers are considered: (1) maximum pixel current location, and (2) average pixel location for two detectors with nearly equal output currents. Wavelength error results for these two methods are compared for some typical wavemeter parameters

Pussy-Willows

https://digitalcommons.library.umaine.edu/mmb-me/1416/thumbnail.jp

STREAMLINING TASK AND DELIVERY ORDER COMPETITIONS WITHIN FEDERAL ACQUISITION REGULATION SUBPART 16.5 FLEXIBILITIES

Includes supplementary materialThe flexibilities offered in Federal Acquisition Regulation (FAR) 16.505 allow contracting officers (COs) to establish streamlined ordering procedures for the award of task orders and delivery orders (TOs/DOs) among existing qualified multiple award contract (MAC) awardees. However, because there is no specific guidance in the FAR or its supplements regarding less formal fair opportunity competition strategies, COs often default to the more familiar FAR Subpart 15.3 procedures. As a result, agencies expend valuable time and resources and potentially waste both in the process. For the Space and Naval Warfare Systems Command, the time and resource constraints associated with frequent competitive MAC orders have led to the desire to identify best practices and perhaps formalize a streamlined approach to award. As such, the purpose of this research is to identify best practices for streamlining local TO/DO awards and provide recommendations for standardized streamlining procedures and documentation. The researchers analyzed 169 sources related to case law and six local MACs as well as policy and regulation to test their hypothesis that local MAC competitions could benefit from streamlining. Their hypothesis was confirmed, and the researchers utilized case law rulings to develop recommendations such as streamlining intentional use of terminology, simplifying evaluations through means like the decision authority and ordering instructions, and simplifying documents such as the BCM.Civilian, Department of the NavyCivilian, Department of the NavyApproved for public release; distribution is unlimited

Book Reviews

Reviews of the following books: Fragile Structures: A Story of Oil Refineries, National Security and the Coast of Maine by Peter Amory Bradford; Maine Catalog: Historic American Buildings Survey, National Park Service, Department of the Interior - A List of Measured Drawings, Photographs and Written Documentation in the Survey compiled and introductory essay by Denys Peter Myers; Journals of the Gloucester Experiment by Gloucester Community Development Corporatio

The Excretion of Sodium Chlorid Solution Injected Subcutaneously

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Accurate in vivo tumor detection using plasmonic-enhanced shifted-excitation Raman difference spectroscopy (SERDS)

For the majority of cancer patients, surgery is the primary method of treatment. In these cases, accurately removing the entire tumor without harming surrounding tissue is critical; however, due to the lack of intraoperative imaging techniques, surgeons rely on visual and physical inspection to identify tumors. Surface-enhanced Raman scattering (SERS) is emerging as a non-invasive optical alternative for intraoperative tumor identification, with high accuracy and stability. However, Raman detection requires dark rooms to work, which is not consistent with surgical settings. Methods: Herein, we used SERS nanoprobes combined with shifted-excitation Raman difference spectroscopy (SERDS) detection, to accurately detect tumors in xenograft murine model. Results: We demonstrate for the first time the use of SERDS for in vivo tumor detection in a murine model under ambient light conditions. We compare traditional Raman detection with SERDS, showing that our method can improve sensitivity and accuracy for this task. Conclusion: Our results show that this method can be used to improve the accuracy and robustness of in vivo Raman/SERS biomedical application, aiding the process of clinical translation of these technologies. © The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See http://ivyspring.com/terms for full terms and conditions

Intervention and Outcomes of Children in Different Types of Listening and Spoken Language Programs

This study explores the impact of the type and dosage of listening and spoken language (LSL) services on speech and language outcomes in children with cochlear implants or hearing aids in two LSL programs. Identical demographic variables were collected across the two programs for use in the statistical analyses. Speech and language outcomes were examined at ages 3 and 5 using standardized test measures. At age 3, significant differences in LSL outcomes existed between programs for children using cochlear implants but not for children using binaural hearing aids. However, at age five, outcomes were similar between the different LSL programs for children with hearing aids and cochlear implants. Total hours of LSL services do not serve as a predictor of LSL outcomes at five years of age. However, early identification of hearing loss, early amplification, and early enrollment in a LSL program were highly influential factors affecting LSL outcomes at three and five years of age. Non-verbal IQ and maternal education levels also influence LSL outcomes. Children with earlier access to hearing technology and LSL intervention may need fewer hours of LSL services to achieve age-appropriate LSL outcomes. Overall, both of these LSL programs supported age-appropriate speech and language outcomes by age 5