Sphenodontians were a successful group of rhynchocephalian reptiles that dominated the fossil record of Lepidosauria during the Triassic and Jurassic. Although evidence of extinction is seen at the end of the Laurasian Early Cretaceous, they appeared to remain numerically abundant in South America until the end of the period. Most of the known Late Cretaceous record in South America is composed...

A single leafy stem from the Middle or lowermost Upper Devonian Campo Chico Formation, Sierra de Perija, western Venezuela, is the first record of the important Devonian herbaceous lycophyte Leclercqia from South America, usually considered as part of western Gondwana. The seemingly cosmopolitan distribution of this genus is discussed in relation to coeval assemblages and palaeocontinental reco...

We examine distance record setting by a random walker in the presence of a measurement error δ and additive noise γ and show that the mean number of (upper) records up to n steps still grows universally as (R(n)) ~ n(1/2) for large n for all jump densities, including Lévy distributions, and for all δ and γ. In contrast, the pace of record setting, measured by the amplitude of the n(1/2) growth,...

The skeletal record of tyrannosaurids is well-documented, whereas their footprint record is surprisingly sparse. There are only a few isolated footprints attributed to tyrannosaurids and, hitherto, no reported trackways. We report the world's first trackways attributable to tyrannosaurids, and describe a new ichnotaxon attributable to tyrannosaurids. These trackways are from the Upper Cretaceou...

Tree structure probing is a significant basic part of target precision spraying. Orchard tree structure digital test system, which consists of three components, is designed by using the ultrasonic sensors. The conveying platform is for fixing and precisely moving the sensor which is used for probing the tree profile. The lower computer can process the test data and communicate with upper comput...

This study focused on the luminescence dating of sediments from Lake El’gygytgyn, a meteorite impact crater 100 km north of the Arctic Circle in northeast Siberia, formed 3.58 Ma ago. The sediment is principally eolian deposited in to a lake with nearly permanently ice. The fine-grained polymineral and quartz extracts taken from nine distinct levels from the upper 12.3 m of sediment core PG1351...

In this paper, we study the performance of estimators of parametersof two-parameter exponential distribution based on upper records. The generalized likelihood ratio (GLR) test was used to generate preliminary test estimator (PTE) for both parameters. We have compared the proposed estimator with maximum likelihood (ML) and unbiased estimators (UE) under mean-squared error (MSE) and Pitman me...

a total of360 iranian combatants who were exposed to mustard gas by the iraqi forces in the war fronts were studied. acute effects and gastrointestinal (gi) complications of sulfur mustard (s m) intoxication were studied separately in iranian combatants admitted to imam reza hospital from january 1984, to may 198x, in order to record the clinical and paraclinical findings, a special examination...