Design and development of the mars observer camera

The Mars Observer Camera (MOC) consists of three integrated optical subassemblies (one narrow-angle and two wide-angle cameras) with common electronics, designed to take high-spatial-resolution pictures of the surface of Mars and lower-spatial-resolution, synoptic coverage of the planet's surface and atmosphere. It incorporates several advanced technologies, including the use of graphite/epoxy structural materials, 32-bit microprocessors, 10⁸-bit digital buffers, and high-speed custom integrated circuits. The cameras use the “push broom” technique to build pictures, one line at a time, as the spacecraft orbits the planet. The narrow-angle camera can acquire images of areas ranging from 2.9 × 2.9 km² to 2.9 × 25.2 km² at a resolution of 1.4 m/pixel. Additionally, lowerresolution pictures (to a lowest resolution of about 11 m/pixel) can be acquired through the narrow-angle camera by pixel averaging; these images can be much longer (up to 2.9 × 500 km at 11 m/pixel). The wide-angle cameras are capable of viewing Mars from horizon to horizon and, in a single 24-hour period, can acquire a complete global image of the planet at a resolution of at least 7.5 km/pixel. Regional areas (covering hundreds of kilometers on a side) may be photographed at a resolution of better than 250 m/pixel at the nadir. The two wide-angle cameras image through a different spectral filter, allowing the construction of color images. The MOC is a cylinder 88 cm in length and about 40 cm in diameter; the redundant electronics, equivalent in complexity and computational power to two engineering workstations, fit within a volume 40 cm in diameter and 10 cm long behind the narrow-angle primary mirror. NASA's Mars Observer mission has adopted a distributed operations philosophy: all uplink and downlink activities for the MOC and the other payload experiments will occur remote from the Jet Propulsion Laboratory's command centers. Following its year-long flight to Mars (launch is scheduled for 16 September 1992), Mars Observer is planned to acquire data for one Mars year (687 Earth days). During that time, MOC will acquire about 2 × 10¹² bits of image and engineering data. During the last three months of the mission, Mars Observer will use a French-supplied relay system to acquire an additional 2 × 10⁹ bits of data from balloons deployed as part of the Soviet Mars '94 mission. These data will be collected and transferred to the Earth through the MOC electronics.     

Adaptive interference cancellation for power line carriercommunication systems

A new technique for adaptive interference cancellation is presented. It has the potential of providing cost-effective interference suppression, thereby freeing up the PLC (power line carrier) frequency band for future expansion of services. A general theory of adaptive cancellation for this application is presented with particular attention paid to several problem areas: error sensing, cancellation bandwidth, and circuit design. It is demonstrated that economical circuit designs that cover the entire PLC frequency band can be readily achieved. These low-level circuits in conjunction with existing PLC components offer a means for achieving high cross-bus attenuation at a significantly lower cost than conventional practice allows     

Coping with the cancer experience. II. Evaluating an education and support programme for cancer patients and their significant others

Inhaled NO has become widely used for diagnosis and therapy of pulmonary hypertension. The potential hazards of NO inhalation include the formation of methemoglobin, formation of NO2, and generation of free radicals in the presence of humidity and oxygen. Careful monitoring of NO and NO2 concentration, and titration of the dose according to a patient's clinical response is essential to minimize toxicity. This paper describes a formula and method that permits calculation and precise control of NO concentration in the inspired gas. The accuracy of the delivery system was assessed by a comparison of calculated and measured NO and NO2 concentrations in a continuous flow ventilator circuit. A comparison of electrochemical detector (ECD) versus chemiluminescence detector (CLD) monitoring techniques showed agreement between the instruments within approximately 2 ppm, with the ECD averaging a higher reading than the calculated or CLD measured values. We deemed a 2 ppm discrepancy between instruments clinically acceptable, and concluded that the instruments could be used interchangeably for clinical purposes to measure NO1 and that the ECD was preferable to CLD for measuring NO2. Details about the equipment are given and techniques are discussed to avoid the risk of inhalation of toxic concentrations of NO and NO2. This method provides the possibility of using inhaled NO with appropriate safety precautions in the range 0-60 ppm in a variety of continuous flow respiratory devices.     

Induction of specific-locus and dominant lethal mutations in male mice by trophosphamide

Trophosphamide induced dominant lethal and specific-locus mutations in spermatozoa and spermatids of mice. The induction pattern of specific-locus and dominant lethal mutations shows two maxima in the mating intervals 1-4 and 9-16 days post treatment. The nature of induced mutations is suggested to be intergenic.     

Risk factors for antisperm antibodies in infertile men

PROBLEM: The prevalence of anti-sperm antibodies (ASAs) in the general population is 0 to 2%; the prevalence in infertile men is much higher at 7 to 26%. However, the role of ASAs in male infertility remains controversial to date. Although several risk factors for ASA development have been defined (such as testicular torsion, varicocele, cryptorchidism, vasectomy, and genital tract infection), there are no specific indications for ASA testing. METHOD: In order to examine if a single parameter exists identifying patients with elevated ASA titers, serum ASA testing was performed with an enzyme-linked immunosorbent assay (ELISA) in 226 consecutive male patients. The new assay, synchron ELISA (Synelisa) used in our study represents a new type of ELISA without fixation of the sperm surface antigens by formaldehyde or glutaraldehyde. Therefore, the quantitative assay is highly sensitive and reproducible since the structure of sperm surface antigens is not altered by the fixation process. RESULTS: The prevalence of ASAs in this population was 14%, while the prevalence of the control group was 2.5%. Of all factors analyzed only a history of vasectomy, an acute epididymitis, and an abnormal result in the bovine mucus penetration test was associated with elevated ASA titers (P < .001). In addition, we could demonstrate a time related formation of ASAs in men after vasectomy. CONCLUSIONS: