The Mars 2020 Perseverance Rover Mast Camera Zoom (Mastcam-Z) Multispectral, Stereoscopic Imaging Investigation.

Mastcam-Z is a multispectral, stereoscopic imaging investigation on the Mars 2020 mission's Perseverance rover. Mastcam-Z consists of a pair of focusable, 4:1 zoomable cameras that provide broadband red/green/blue and narrowband 400-1000 nm color imaging with fields of view from 25.6° × 19.2° (26 mm focal length at 283 µrad/pixel) to 6.2° × 4.6° (110 mm focal length at 67.4 µrad/pixel). The cameras can resolve (≥ 5 pixels) ∼0.7 mm features at 2 m and ∼3.3 cm features at 100 m distance. Mastcam-Z shares significant heritage with the Mastcam instruments on the Mars Science Laboratory Curiosity rover. Each Mastcam-Z camera consists of zoom, focus, and filter wheel mechanisms and a 1648 × 1214 pixel charge-coupled device detector and electronics. The two Mastcam-Z cameras are mounted with a 24.4 cm stereo baseline and 2.3° total toe-in on a camera plate ∼2 m above the surface on the rover's Remote Sensing Mast, which provides azimuth and elevation actuation. A separate digital electronics assembly inside the rover provides power, data processing and storage, and the interface to the rover computer. Primary and secondary Mastcam-Z calibration targets mounted on the rover top deck enable tactical reflectance calibration. Mastcam-Z multispectral, stereo, and panoramic images will be used to provide detailed morphology, topography, and geologic context along the rover's traverse; constrain mineralogic, photometric, and physical properties of surface materials; monitor and characterize atmospheric and astronomical phenomena; and document the rover's sample extraction and caching locations. Mastcam-Z images will also provide key engineering information to support sample selection and other rover driving and tool/instrument operations decisions.

Vagal-induced tachycardia: release of vasoactive intestinal peptide and peptide HI.

The relationship between vagal-induced tachycardia (VT) and release of vasoactive intestinal peptide (VIP) and peptide HI (PHI) into cardiac lymph and coronary sinus blood was studied in 23 alpha-chloralose-anesthetized open-chest dogs that were autonomically decentralized and pretreated with atropine and propranolol. After simultaneous right and left cervical vagal stimulation at 5 V, 20 Hz for 3 min mean +/- SE, increase in heart rate was 38 +/- 6 beats/min, and increase in lymph VIP output from control was 0.308 +/- 0.093 pg/min (P = 0.004). The decrease in VIP arterial minus coronary sinus concentration was not significant. The increase in heart rate did not significantly correlate with increase in lymph VIP output (R2 = 0.141) or decrease in VIP arterial minus coronary sinus concentration (R2 = 0.059). The increases in heart rate and lymph VIP output were blocked by hexamethonium. Increase in lymph PHI output from control during VT (5 dogs) was 0.797 +/- 0.658 pg/min. Arterial-coronary sinus PHI concentration difference did not change in these dogs. These data indicate that VT is associated but not significantly correlated with VIP and PHI release into cardiac lymph. Cholinoceptive nicotinic receptors may mediate VIP release and VT in anesthetized dogs.

Postnatal development of peptidergic innervation of the canine heart.

The autonomic innervation of the canine heart develops with considerable regional asymmetry during the early neonatal period. To examine the development of the peptidergic component of the innervation, 28 mongrel puppies 1-6 weeks of age from five litters were studied at weekly intervals. Four of the mothers were also studied as adult and breed controls. Tissue neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) concentrations were determined by radioimmunoassay in myocardial specimens obtained from several specific sites of the cardiac chambers and from the proximal coronary arteries. Data were analysed according to age, cardiac chamber/vessel, gender and individual litter. In general, NPY concentrations in pg/mg protein were six- to eight-fold higher than those of VIP. Also concentrations for both peptides were about two-fold higher in the coronary arteries than the myocardium and differed among chambers, being higher and similar in the atria and lower in the ventricles, particularly for NPY. No gender differences were identified. Concentrations varied among litters, but the developmental pattern was similar with the highest peptide concentrations identified in the first and fourth week. Whereas the differences among chambers may also reflect differing rates of developmental increase of myocardial mass, the pattern corresponds only in part to previously identified functional changes in sympathetic innervation since, in contrast to previous findings, high NPY concentrations in the first 2 weeks suggest anatomically advanced innervation.