The Space Technology 7 Disturbance Reduction System (ST7-DRS) is a NASA technology demonstration payload that operated from January 2016 through July of 2017 on the European Space Agency's LISA Pathfinder spacecraft. The joint goal of the NASA and ESA missions was to validate key technologies for a future space-based gravitational wave observatory targeting the source-rich milliHertz band. The two primary components of ST7-DRS are a micropropulsion system based on colloidal micro-Newton thrusters (CMNTs) and a control system that simultaneously controls the attitude and position of the spacecraft and the two free-flying test masses (TMs). This paper presents our main experimental results and summarizes the overall the performance of the CMNTs and control laws. We find that the CMNT performance to be consistent with pre-flight predictions, with a measured system thrust noise on the order of 100 nN/ √ Hz in the 1 mHz ≤ f ≤ 30 mHz band. The control system maintained the TM-spacecraft separation with an RMS error of less than 2 nm and a noise spectral density of less than 3 nm/ √ Hz in the same band. Thruster calibration measurements yield thrust values consistent with the performance model and ground-based thrust-stand measurements, to within a few percent. We also report a differential acceleration noise between the two test masses with a spectral density of roughly 3 fm/s 2 / √ Hz in the 1 mHz ≤ f ≤ 30 mHz band, slightly less than twice as large as the best performance reported with the baseline LISA Pathfinder configuration and below the current requirements for the Laser Interferometer Space Antenna (LISA) mission.
Radio occultation measurements were made at approximately 50 locations on Mars with the Viking Orbiter 1 S (2.3 GHz) and X (8.4 GHz) band tracking links during October 1976. The measurements have been used to study the topography and atmosphere of Mars at latitudes ranging from about 75°S to 70°N. By using the ingress and egress times obtained from the observed limb diffraction effects together with the best ephemerides available for the orbiter and the planet we have determined the surface elevations at the occultation points relative to the reference areoid. The observations agree with Mariner 9 and radar data to within 2 km. The mean atmospheric pressure at the areoid level was found to be 5.9 mbar during the northern midsummer season, a value which agrees quite well with data obtained at the landing sites. By comparing the new electron density measurements with earlier Mariner data we have determined that the temperature and the plasma scale height of the upper atmosphere appear to be functions of solar activity.
Objective:In India, various groups have studied different regions to find out deletion pattern of dystrophin gene. We have investigated its deletion pattern among Duchenne/Becker muscular dystrophy (D/BMD) patients across Gujarat. Moreover, in this study we also correlate the same with reading frame rule. However, we too consider various clinicopathological features to establish as adjunct indices when deletion detection fails.Materials and Methods:In this pilot study, a total of 88 D/BMD patients consulting at our centers in Gujarat, India were included. All patients were reviewed on basis of their clinical characteristics, tested by three primer sets of 10-plex, 9-plex, and 7-plex polymerase chain reaction (PCR) for genetic analysis; whereas, biochemical indices were measured using automated biochemical analyzers.Results:The diagnosis of D/BMD was confirmed by multiplex-PCR (M-PCR) in D/BMD patients. A number of 65 (73.86%) out of 88 patients showed deletion in dystrophin gene. The exon 50 (58.46%) was the most frequent deletion found in our study. The mean age of onset of DMD and BMD was 4.09 ± 0.15 and 7.14 ± 0.55 years, respectively. In patients, mean creatine phosphokinase (CPK), lactate dehydrogenase (LDH), and myoglobin levels were elevated significantly (P < 0.05) in comparison to controls. Addition to CPK, LDH and myoglobin are good adjunct when deletion detection failed. These data are further in accordance with world literature when correlated with frame rule.Conclusion:The analysis has been carried out for the first time for a total of 88 D/BMD patients particularly from Gujarat, India. More research is essential to elucidate specific mutation pattern in association with management and therapies of proband.
The zodiacal dust complex, a population of dust and small particles that pervades the solar system, provides important insight into the formation and dynamics of planets, comets, asteroids, and other bodies. We present a new set of data obtained from direct measurements of momentum transfer to a spacecraft from individual particle impacts. This technique is made possible by the extreme precision of the instruments flown on the LISA Pathfinder spacecraft, a technology demonstrator for a future space-based gravitational wave observatory. Pathfinder employed a technique known as drag-free control that achieved rejection of external disturbances, including particle impacts, using a micropropulsion system. Using a simple model of the impacts and knowledge of the control system, we show that it is possible to detect impacts and measure properties such as the transferred momentum, direction of travel, and location of impact on the spacecraft. In this paper, we present the results of a systematic search for impacts during 4348 hr of Pathfinder data. We report a total of 54 candidates with transferred momenta ranging from 0.2 to 230 μNs. We furthermore make a comparison of these candidates with models of micrometeoroid populations in the inner solar system, including those resulting from Jupiter-family comets (JFCs), Oort Cloud comets, Halley-type comets, and asteroids. We find that our measured population is consistent with a population dominated by JFCs, with some evidence for a smaller contribution from Halley-type comets, in agreement with consensus models of the zodiacal dust complex in the momentum range sampled by LISA Pathfinder.
Dystrophy Society, Ahmedabad, Gujarat, India) with complaints of walking difficulties and bilateral calf hypertrophy for the past 2 years. The painless hypertrophy was slow in progression. Proband have had weakness in distal muscles though self-ambulatory. On visual examinations, there were nonattendances of Gower's sign as well as scoliosis, which were found to be signs of BMD-type MDs [Figure 1]. Moreover, the boy did not experience any innate anomalies or no familial history for the same [Figure 2]. Muscular dystrophies (MDs) are broad group of muscle illness. Duchenne muscular dystrophy (DMD) and allelic Becker muscular dystrophy (BMD) are the most common forms of MDs, together termed as dystrophinopathy. A margin line between DMD and BMD is only justified by the presence of dystrophin protein along with muscle strength. Here, we report a first case of large deletion with BMD phenotype of an 11-year-old Gujarati boy. This inimitable case has been reported for its uniqueness and to attest the magnitude of molecular screening for diagnosis as well as hint for development of new therapeutics.
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