Hematologic, hepatic, and renal function changes in hospitalized patients with Middle East respiratory syndrome coronavirus

Background There are no longitudinal data on the changes in hematologic, hepatic, and renal function findings in patients with Middle East respiratory syndrome coronavirus (MERS‐CoV) infection. Methods This is a retrospective cohort study of 16 MERS‐CoV patients, to describe the hematological, hepatic, and renal findings of patients with MERS‐CoV. Results During the 21 days of observation, there was no significant change in the hepatic panel or creatinine tests. There was a significant increase in the mean ± SD of the white blood cell count from 8.3 ± 4.6 to 14.53 ± 7 (P value = 0.001) and an increase in mean ± SD of the absolute neutrophil count from 6.33 ± 4.2 to 12 ± 5.5 (P value = 0.015). Leukocytosis was observed in 31% (5/16) of the patients on day 1 and in 80% (4/5) on day 21. Transient leukopenia developed in 6% (1/16) of the patients on day 1 and in 13% (1/8) on day 8. None of the patients had neutropenia. Lymphopenia was a prominent feature with a rate of 44% (7/16) of the patients on day 1 and 60% (3/5) on day 21. Lymphocytosis was not a feature of MERS‐CoV infection. Thrombocytopenia developed in 31% (5/16) of the patients on day 1 and 40% (2/5) on day 21. Thrombocytosis was not a prominent feature and was observed in 6% (1/16) of the patients on day 1 and 17% (1/6) on day 9. Conclusions Patients with MERS‐CoV infection showed variable hematologic parameters over time. Lymphocytosis and neutropenia were not features of MERS‐CoV infection

L-band mobile terminal antennas for helicopters

The feasibility of using a low gain antenna (LGA) as a mobile terminal antenna for a helicopter is described in this paper. The objectives are to select the lowest cost antenna system which can be easily mounted on a helicopter and capable of communicating with a satellite, and to determine the best antenna position on the helicopter to mitigate the signal blockage due to rotor blades and the multipath effect from the helicopter's body. The omnidirectional LGA is selected because it is simple, reliable, and low cost. The helix antenna is selected among the many LGA's because it is the most economical one and has the widest elevation beamwidth. Both 2-arm and 4-arm helices are studied experimentally to determine the antenna's performance and the scattering effects from the helicopter's body. It is found that the LGA should be located near the tail section and at least eight inches above the helicopter

The Pioneer Anomaly

Radio-metric Doppler tracking data received from the Pioneer 10 and 11 spacecraft from heliocentric distances of 20-70 AU has consistently indicated the presence of a small, anomalous, blue-shifted frequency drift uniformly changing with a rate of ~6 x 10^{-9} Hz/s. Ultimately, the drift was interpreted as a constant sunward deceleration of each particular spacecraft at the level of a_P = (8.74 +/- 1.33) x 10^{-10} m/s^2. This apparent violation of the Newton's gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. In this review, we summarize the current knowledge of the physical properties of the anomaly and the conditions that led to its detection and characterization. We review various mechanisms proposed to explain the anomaly and discuss the current state of efforts to determine its nature. A comprehensive new investigation of the anomalous behavior of the two Pioneers has begun recently. The new efforts rely on the much-extended set of radio-metric Doppler data for both spacecraft in conjunction with the newly available complete record of their telemetry files and a large archive of original project documentation. As the new study is yet to report its findings, this review provides the necessary background for the new results to appear in the near future. In particular, we provide a significant amount of information on the design, operations and behavior of the two Pioneers during their entire missions, including descriptions of various data formats and techniques used for their navigation and radio-science data analysis. As most of this information was recovered relatively recently, it was not used in the previous studies of the Pioneer anomaly, but it is critical for the new investigation.Comment: 165 pages, 40 figures, 16 tables; accepted for publication in Living Reviews in Relativit

Optimum Strategies for Monitoring the Operational Status of a Spacecraft

The design of a spacecraft-monitoring system based on a Neyman{Pearson detec-tion criterion is discussed. Each noncatastrophic state of the spacecraft is indicated by the transmission of a speciflc signal to the ground station. Complete failure of the spacecraft is indicated by the transmission of no signal. The set of signals chosen to represent the spacecraft states consists of a group of orthogonally spaced (in frequency) carriers each with unknown (random) phase. Receiver structures derived from maximum-likelihood considerations are proposed that provide suit-able performance in the presence of frequency uncertainty (due to Doppler) and frequency rate uncertainty (due to oscillator drift). Numerical results are obtained from a combination of analysis and simulation and indicate the trade-ofis among the various receiver structures between performance and implementation complexity. I