A high frequency GaAlAs travelling wave electro-optic modulator at 0.82 micrometers

Experimental GaAlAs modulators operating at 0.82 micrometers using a Mach-Zehnder interferometer configuration were designed and fabricated. Coplanar 50 ohm travelling wave microwave electrodes were used to obtain a bandwidth length product of 11.95 GHz-cm. The design, fabrication and dc performance of the GaAlAs travelling wave modulator is presented

Microwave characteristics of GaAs MMIC integratable optical detectors

Interdigitated photoconductive detectors were fabricated on microwave device structures, making them easily integratable with Monolithic Microwave Integrated Circuits (MMIC). Detector responsivity as high as 2.5 A/W and an external quantum efficiency of 3.81 were measured. Response speed was nearly independent of electrode geometry, and all detectors had usable response at frequencies to 6 GHz. A small signal model of the detectors based on microwave measurements was also developed

Intraclass correlation coefficients for cluster randomized trials in care pathways and usual care: hospital treatment for heart failure.

BACKGROUND: Cluster randomized trials are increasingly being used in healthcare evaluation to show the effectiveness of a specific intervention. Care pathways (CPs) are becoming a popular tool to improve the quality of health-care services provided to heart failure patients. In order to perform a well-designed cluster randomized trial to demonstrate the effectiveness of Usual care (UC) and CP in heart failure treatment, the intraclass correlation coefficient (ICC) should be available before conducting a trial to estimate the required sample size. This study reports ICCs for both demographical and outcome variables from cluster randomized trials of heart failure patients in UC and care pathways. METHODS: To calculate the degree of within-cluster dependence, the ICC and associated 95% confidence interval were calculated by a method based on analysis of variance. All analyses were performed in R software version 2.15.1. RESULTS: ICCs for baseline characteristics ranged from 0.025 to 0.058. The median value and interquartile range was 0.043 [0.026-0.052] for ICCs of baseline characteristics. Among baseline characteristics, the highest ICCs were found for admission by referral or admission from home (ICC = 0.058) and the disease severity at admission (ICC = 0.046). Corresponding ICCs for appropriateness of the stay, length of stay and hospitalization cost were 0.069, 0.063, and 0.001 in CP group and 0.203, 0.020, 0.046 for usual care, respectively. CONCLUSION: Reported values of ICCs from present care pathway trial and UC results for some common outcomes will be helpful for estimating sample size in future clustered randomized heart failure trials, in particular for the evaluation of care pathways

Multislice/multidetector-row computed tomography findings of a rare coronary anomaly: the first septal perforator branch originating from the left main coronary artery

Multislice/multidetector-row computed tomography (MDCT) is now widely used for noninvasive assessment of coronary arteries, and it may sometimes reveal coronary anomalies. Detection of such anomalies may be relevant both during follow-up and for planning cardiac or coronary surgical/interventional procedures. These anomalies may be missed unless carefully sought. In this paper, we present the MDCT images of a first septal perforator branch originating from the left main coronary artery, which represents an extremely rare coronary anomaly. To the bestof our knowledge, this is the first case in the literature where MDCT images are presented

Association of change in body condition score with milk yield and reproduction traits of holstein cows

The aim of the study was to determine the effect of changes in body condition score (BSC) on milk yield and reproduction traits in early (30, 60 and 90 d), mid (120 and 150 d) and late lactation (210 and 270 d) in Holstein cows raised on a private dairy cattle farm in Kırşehir, Turkey. The data were obtained from 140 cows calved from November 2014 to November 2015. BSC groups were categorized as low, moderate and high in early lactation ([removed]3.00), mid-lactation ([removed]3.25) and late lactation ([removed]3.50). Cows with low and moderate BCS in early (BCS<2.75 and BCS=2.75-3.00), mid (BCS<3.00 and BCS=3.00–3.25) and late lactation (BCS[removed]3.50) had a higher daily milk yield (DMY), lactation milk yield (LMY) and 305-day milk yield (305-dMY) (P<0.05). Reproduction traits were also affected (P<0.05) by BCS in mid-lactation. In mid-lactation, the cows with low and moderate BCS had a shorter period of calving to the first service interval (CFSI) and lower number of services per conception (NSC) than that of the cows with high BCS (P<0.05). Both milk yield and reproduction traits were adversely affected by high BCS. It is suggested that BCS can be used as a reliable indicator in indirect selection programs for higher milk yield and reproductive performance in Holstein cows. © 2020, Pakistan Agricultural Scientists Forum. All rights reserved

Lunar Communication Terminals for NASA Exploration Missions: Needs, Operations Concepts and Architectures

NASA is conducting architecture studies prior to deploying a series of short- and long-duration human and robotic missions for the exploration of the Moon and Mars under the Vision for Space Exploration Initiative. A key objective of these missions is to establish and expand, through a series of launches, a system of systems approach to exploration capabilities and science return. The systems identified were Crew Exploration Vehicles, crew and cargo launch vehicles, crew EVA suits, crew and cargo landers, habitats, mobility carriers, and small, pressurized rovers. Multiple space communication networks and systems, deployed over time, will support these space exploration systems of systems. Each deployment phase will support interoperability of components and provide 20 years of legacy systems. In this paper, we describe the modular lunar communications terminals needed for the emerging lunar mission operational scenarios. These lunar communication terminals require flexibility for use in stationary, integrated, and mobile environments. They will support links directly to Earth, to lunar relay satellites, to astronauts and to fixed and mobile lunar surface systems. The operating concepts and traffic models are presented for these terminals within variety of lunar scenarios. A preliminary architecture is outlined, providing for suitable long-duration operations in the harsh lunar environment

NASA Space applications of high-temperature superconductors

The application of superconducting technology in space has been limited by the requirement of cooling to near liquid helium temperatures. The only means of obtaining these temperatures has been with cryogenic fluids which severely limit mission lifetime. The development of materials with superconducting transition temperatures above 77 K has made superconducting technology more attractive and feasible for employment in aerospace systems. Here, potential applications of high temperature superconducting technology in cryocoolers, remote sensing, communications, and power systems are discussed

Simulation of a NASA LEO Satellite Hybrid Network

Various issues associated with "Simulation of a NASA LEO Satellite Hybrid Network" are presented in viewgraph form. Specific topics include: 1) Objective of the investigation; 2) Satellite orbit description and included nodes; 3) TCP and FTP simulation descriptions; 4) Simulation results; and 5) Derived conclusions