1,453 research outputs found
Apollo experience report: The role of flight mission rules in mission preparation and conduct
The development of flight mission rules from the mission development phase through the detailed mission-planning phase and through the testing and training phase is analyzed. The procedure for review of the rules and the coordination requirements for mission-rule development are presented. The application of the rules to real-time decision making is outlined, and consideration is given to the benefit of training ground controllers and flightcrews in the methods of determining the best response to a nonnominal in-flight situation for which no action has been preplanned. The Flight Mission Rules document is discussed in terms of the purpose and objective thereof and in terms of the definition, the development, and the use of mission rules
EVOLUTIONARY TRENDS IN TRIASSIC DICYNODONTIA
Triassic Dicynodontia differ from most of their Permian ancestors in a number of
specialisations that reach extremes in the Upper Triassic. These are ( 1) increase in total body size,
(2) increase in the relative length of the snout and secondary palate by backward growth of the
premaxilla, (3) reduction in the length of the fenestra medio-palatinalis combined with
posterior migration out of the choanal depression, (4) shortening and dorsal expansion of the
intertemporal region, (5 ) fusion of elements in the front part of the brain-case, (6) posterior
migration of the reflected lamina of the mandible, (7) disappearance of the quadrate foramen
and the development of a process of the quadrate that extends along the quadrate ramus of the
pterygoid. It is thought that the occurrence of the last feature in Dinodontosaurus platygnathw Cox
and Jacheleria colorata Bonaparte warrants the transfer of the species platygnathus to the genus
Jacheleria and the erection of a new subfamily, Jachelerinae nov.
It is concluded that the specialisations of the Triassic forms can be attributed to adaptation to
a Dicroidium-dominated flora
A NEW TRIASSIC VERTEBRATE FAUNA FROM SOUTH WEST AFRICA
A new fauna of mammal-like reptiles is described from a continental sequence of
sediments in South West Africa hitherto known as the Etjo Beds. These include
representatives of the Anomodontia (two new forms and one known from the Karroo
basin), Bauriamorpha, (one specimen comparable with a known form), Cynodontia (one
new form and two known from the Karroo basin) and one small eriopoid amphibian. On
the basis of this faunal assemblage it can be shown that there is a disconformity between
the upper Plateau Sandstone Formation containing traces of Dinosaurs of possible
Carnian-Norian age and a lower Omingonde Mudstone Formation with this new fauna,
of essentially Upper Beaufort (Scythian/Anisian) age. The two formations are
distinguished on lithological grounds. The Triassic sequence in the neighbouring Doros
area is thought to be equivalent to the Plateau Sandstone Formation
The palaeontology of Haasgat a preliminary account
Haasgat is a cave on the steep western slope of the upper reach of the Witwatersrand Spruit, on the farm Leeuwenkloof 480 lQ, in the Brits District. It was heavily mined for flowstone (calcite). The cave contains a deposit offossiliferous cave silt and breccia that was partially removed by the miners and dumped on the steep slopes of the valley. The original entrance was probably a shallow inclined pit, leading into an upper chamber and then into the preserved depository. Both porcupines and carnivores served as accumulating agents for the bones. Fossils of the primates Parapapio and Cercopifhecoides, hyaena (Chasmaporthetes), fox, porcupines, several species of bovids and two species of Hyrax have been recovered. An insufficient number of fossils have been prepared to determine the age of the deposit with certainty. The deposit was provisionally thought to be of Pliocene age because of the occurrence of Parapapio. At this stage it would be unwise to correlate this occurrence with any other caves in this age range. It is concluded that the cave silts were deposited by flash floods, under a wetter climatic regime than that of the present
A RE-EVALUATION OF THE GENUS TROPIDOSTOMA SEELEY
The type specimens of Cteniosaurus platyceps Broom, Dicynodon acutirostris
Broom, and Dicynodon validus Broom were re-examined and were found to be very
similar in a number of features rarely encountered in other Anomodontia. The skull of
the type of Cteniosaurus platyceps is described in some detail. It is concluded that the
above species must be considered to be junior synonyms of Tropidostoma microtrema
(Seeley)
A RE-EVALUATION OF THE SYSTEMATICS AND MORPHOLOGY OF CERTAIN ANOMODONT THERAPSIDA
The cranial morphology of a number of
specimens assigned to the genera Oudenodon,
Rhachiocephalus, Aulacephalodon and Pelanomodon
was investigated (Keyser, 1969). It was
found that the internal morphology and the
general structure of the skulls show great agreement.
Many of the differences between the genera
can be associated with the size of the skull. The
main differences between the genera lie in the
specialisation of the biting mechanism and in the
relative size and shape of the nasal and prefrontal
bosses. It is suggested that the genera Oudenodon
and Rhachio cephalus bit off their food with the
sides of the horn-covered jaws while the broadnosed
genera Aulacephalodon and Pelanomodon
bit with the transverse anterior tips of the jaws.
This difference in the morphology of the jaws is
probably indicative of a fundamental dichotomy
between the two groups of genera. A similar
dichotomy has been suggested for Triassic dicynodonts
by Cox (1965)
Copyright For The Rest Of Us: A guide for people who aren\u27t lawyers
For those who want to teach or learn more about American copyright law, Copyright For The Rest Of Us is the book to use. Eleven chapters, with illustrations, outline concepts such as basic copyright law, where to find it, and how to apply copyright law in many common situations. Each chapter includes a set of scenarios or discussion questions for use on your own or in class
Improved VAS regression soundings of mesoscale temperature structure observed during the 1982 atmospheric variability experiment
An Atmospheric Variability Experiment (AVE) was conducted over the central U.S. in the spring of 1982, collecting radiosonde date to verify mesoscale soundings from the VISSR Atmospheric Sounder (VAS) on the GOES satellite. Previously published VAS/AVE comparisons for the 6 March 1982 case found that the satellite retrievals scarcely detected a low level temperature inversion or a mid-tropospheric cold pool over a special mesoscale radiosonde verification network in north central Texas. The previously published regression and physical retrieval algorithms did not fully utilize VAS' sensitivity to important subsynoptic thermal features. Therefore, the 6 March 1982 case was reprocessed adding two enhancements to the VAS regression retrieval algorithm: (1) the regression matrix was determined using AVE profile data obtained in the region at asynoptic times, and (2) more optimistic signal-to-noise statistical conditioning factors were applied to the VAS temperature sounding channels. The new VAS soundings resolve more of the low level temperature inversion and mid-level cold pool. Most of the improvements stems from the utilization of asynoptic radiosonde observations at NWS sites. This case suggests that VAS regression soundings may require a ground-based asynoptic profiler network to bridge the gap between the synoptic radiosonde network and the high resolution geosynchronous satellite observations during the day
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