As the major field in petroleum reserve growth, fractured-vuggy reservoir is the key research in the future. However, in the development of fracture-cavity reservoir, collapse may occur in karst cave which greatly affects the oil well output. In order to forecast the cave collapse before drilling, this work adopts the method of span dichotomy reduction to determine the critical karst collapse o...

Cave geometric properties have been studied between 1958 and today as statistical or fractal objects. These studies have divulged some degree of order in such properties as the distribution of cave lengths in a region and the distribution of cave passage sizes, and exhibiting some degree of self-similarity, suggesting a fractal nature, or moderate departures from self-similarity, suggesting geo...

Combining augmented reality (AR) environments with immersive virtual environments (VEs) can reduce interaction gaps and provide embodied interactions in distributed collaborative works. It can also provide many opportunities and degrees of freedom for collaboration in both real and virtual worlds. A gesture based AR environment provides variety of input and output modalities to networked and di...

A total of eight Ensifer sp. strains were isolated from two pristine cave environments. One strain was isolated from a cave water pool located in the Wind Cave National Park, South Dakota, USA and the remaining seven strains were isolated from Lechuguilla Cave of Carlsbad Caverns National Park, New Mexico, USA. Whole genome sequencing and comparative genomic analyses of the eight isolates compa...

Research on the development of virtual environments has been limited to date to universities due to the high cost of equipment and high-speed internet access. Applications of virtual environments using CAVE technology are numerous in medicine, architecture, military weapons systems, medicine, science research and business training. However, the cost of this emerging technology has prevented the...

In the study, the growth traits, photosynthesis and morphology characteristics of several cultivars of switchgrass (Panicum virgatum L.) have been assessed the yield potential and adaptability in diverse environments (Yangling, Dingbian of Shaanxi province, Guyuan of Ningxia) on the Loess Plateau of China. Alamo was the best adapted switchgrass cultivar for biomass production in Yangling with d...

BACKGROUND Closely related lineages of livebearing fishes have independently adapted to two extreme environmental factors: toxic hydrogen sulphide (H(2)S) and perpetual darkness. Previous work has demonstrated in adult specimens that fish from these extreme habitats convergently evolved drastically increased head and offspring size, while cave fish are further characterized by reduced pigmentat...

Procedural content generation is becoming an increasingly popular research area as a means of algorithmically generating scene content for virtual environments. The automated generation of such content avoids the manual labour typically associated with creating scene content, and is extremely useful in application areas such as computer graphics, movie production and video games. While virtual ...

Visually guided action implies the existence of information as well as a control law relating that information to movement. For ball catching, the Chapman Strategy--keeping constant the rate of change of the tangent of the elevation angle (d(tan(alpha))/dt)--leads a catcher to the right location at the right time to intercept a fly ball. Previous studies showed the ability to detect the informa...

BACKGROUND The endemic and threatened troglobites (organisms restricted to caves) Charinus eleonorae (Amblypygi) and Iandumoema uai (Opiliones), both from Olhos d'Água cave, located at Peruaçu Caves National Park (southeast Brazil), have their distribution expanded for a new locality inside of the National Park (Lapa do Cipó cave), extending their distribution at least in 9.5km(2). NEW INFORM...