Texas A&M University

About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Finite element method. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.

The Importance of Resources in the Internationalization of Professional Service Firms: The Good, the Bad, and The Ugly

Abstract: To further knowledge about the bases of internationalization, we examined the importance of two firm resources: human capital, and relational capital derived from relations with corporate clients a...

Materials science challenges for high-temperature superconducting wire

Abstract: Twenty years ago in a series of amazing discoveries it was found that a large family of ceramic cuprate materials exhibited superconductivity at temperatures above, and in some cases well above, that of liquid nitrogen. Imaginations were energized by the thought of applications for zero-resistance conductors cooled with an inexpensive and readily available cryogen. Early optimism, however, was soon tempered by the hard realities of these new materials: brittle ceramics are not easily formed into long flexible conductors; high current levels require near-perfect crystallinity; and — the downside of high transition temperature — performance drops rapidly in a magnetic field. Despite these formidable obstacles, thousands of kilometres of high-temperature superconducting wire have now been manufactured for demonstrations of transmission cables, motors and other electrical power components. The question is whether the advantages of superconducting wire, such as efficiency and compactness, can outweigh the disadvantage: cost. The remaining task for materials scientists is to return to the fundamentals and squeeze as much performance as possible from these wonderful and difficult materials.

The role of microbes in accretion, lamination and early lithification of modern marine stromatolites

Abstract: For three billion years, before the Cambrian diversification of life, laminated carbonate build-ups called stromatolites were widespread in shallow marine seas. These ancient structures are generally thought to be microbial in origin and potentially preserve evidence of the Earth's earliest biosphere. Despite their evolutionary significance, little is known about stromatolite formation, especially the relative roles of microbial and environmental factors in stromatolite accretion. Here we show that growth of modern marine stromatolites represents a dynamic balance between sedimentation and intermittent lithification of cyanobacterial mats. Periods of rapid sediment accretion, during which stromatolite surfaces are dominated by pioneer communities of gliding filamentous cyanobacteria, alternate with hiatal intervals. These discontinuities in sedimentation are characterized by development of surface films of exopolymer and subsequent heterotrophic bacterial decomposition, forming thin crusts of microcrystalline carbonate. During prolonged hiatal periods, climax communities develop, which include endolithic coccoid cyanobacteria. These coccoids modify the sediment, forming thicker lithified laminae. Preservation of lithified layers at depth creates millimetre-scale lamination. This simple model of modern marine stromatolite growth may be applicable to ancient stromatolites.

Long‐Term Recurrence Rates in Previously Untreated (Primary) Basal Cell Carcinoma: Implications for Patient Follow‐Up

Abstract: We reviewed all studies (since 1947) reporting recurrence rates for treatment of primary (previously untreated) basal cell carcinomas using surgical excision, radiotherapy, cryotherapy, curettage and electrodesiccation, and Mohs micrographic surgery. Our findings indicate that recurrences following treatment of primary basal cell carcinoma appear later than is generally acknowledged in the literature. We found that less than one-third of all recurrences appear in the first year following treatment; only 50% appear within the first 2 years following treatment; and only 66%, or nearly two-thirds, appear within the first 3 years following treatment. A good rule of thumb is that the 10-year recurrence rate is double, or 2 times, that of the 2-year recurrence rate. Furthermore, 18% of recurrences appear between the fifth and tenth year following treatment. These results held true, irrespective of treatment modality examined. Seventy-two studies reporting short-term recurrence rates (follow-up less than 5 years) had a weighted average recurrence rate of 4.2%, whereas 34 long-term studies (follow-up of 5 years) had a weighted average recurrence rate of 8.7%, or more than 2 times the short-term rate. Five-year recurrence rates by treatment modality are as follows: Mohs micrographic surgery 1.0%, surgical excision 10.1%, curettage and electrodesiccation 7.7%, radiation therapy 8.7%, and cryosurgery 7.5%. We conclude that the reporting of recurrence rate data for basal cell carcinoma should be standardized using 5-year life table analysis, and even more important is our conclusion that lifetime follow-up is necessary after treatment of primary basal cell carcinoma in order both recurrences and new primaries.