University of Houston

About: University of Houston is a education organization based out in Houston, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23074 authors who have published 53903 publications receiving 1641968 citations.

Adaptive optics scanning laser ophthalmoscopy

Abstract: We present the first scanning laser ophthalmoscope that uses adaptive optics to measure and correct the high order aberrations of the human eye. Adaptive optics increases both lateral and axial resolution, permitting axial sectioning of retinal tissue in vivo. The instrument is used to visualize photoreceptors, nerve fibers and flow of white blood cells in retinal capillaries.

The Galveston Orientation and Amnesia Test. A practical scale to assess cognition after head injury.

Abstract: The Galveston Orientation and Amnesia Test (GOAT) was developed to evaluate cognition serially during the subacute stage of recovery from closed head injury. This practical scale measures orientation to person, place, and time, and memory for events preceding and following the injury. The distribution of test scores in 50 patients who had recovered from a mild closed head injury was used to define the range of variation in performance and to analyze the effects of demographic factors. In a validity study of 52 closed head-injured patients, the duration of impaired GOAT scores was strongly related to the acute neurosurgical ratings of eye opening, motor responding, and verbal responding on the Glasgow Coma Scale. Duration of post-traumatic amnesia, as defined by the persistence of defective GOAT scores, was longer in patients with computed tomographic evidence of diffuse or bilateral brain injury as compared to cases with focal unilateral lesions. Serial GOAT scores were also predictive of long term level of recovery. Review of the brief cognitive test literature disclosed that several techniques have adequate validity data substantiating their use in the detection of dementia in geriatric, psychiatric, and medical populations. Recommendations for the clinical application of the various brief cognitive tests are discussed.

Functional- and abundance-based mechanisms explain diversity loss due to N fertilization.

Abstract: Human activities have increased N availability dramatically in terrestrial and aquatic ecosystems. Extensive research demonstrates that local plant species diversity generally declines in response to nutrient enrichment, yet the mechanisms for this decline remain unclear. Based on an analysis of >900 species responses from 34 N-fertilization experiments across nine terrestrial ecosystems in North America, we show that both trait-neutral and trait-based mechanisms operate simultaneously to influence diversity loss as production increases. Rare species were often lost because of soil fertilization, randomly with respect to traits. The risk of species loss due to fertilization ranged from >60% for the rarest species to 10% for the most abundant species. Perennials, species with N-fixing symbionts, and those of native origin also experienced increased risk of local extinction after fertilization, regardless of their initial abundance. Whereas abundance was consistently important across all systems, functional mechanisms were often system-dependent. As N availability continues to increase globally, management that focuses on locally susceptible functional groups and generally susceptible rare species will be essential to maintain biodiversity.