At least 13 times during the Pleistocene Epoch lava flowed into the inner gorge of the Grand Canyon and formed lava dams, as high as 600 m, that temporarily blocked the flow of the Colorado River. K-Ar ages on these lava dams indicate that the seven youngest formed within a short period of time between about 0.6 and 0.4 mega-annum (Ma). The physiography of the lava dam remnants within the canyo...

While most large river-deltas in the world are facing the risk of subsidence and erosion in the Anthropocene, it is suspected that the Changjiang submerged delta (CSD) could be subjected to the impacts of the world's largest dam, the Three Gorges Dam (TGD). Here we firstly indicate that the CSD went through high accumulation (1958-1978); slight accumulation (1978-1997), slight erosion (1997-200...

OBJECTIVES Use of a rubber dam during root canal treatment is considered the standard of care because it enhances patient safety and optimises the odds of successful treatment. Nonetheless, not all dentists use a rubber dam, creating disconnect between presumed standard of care and what is actually done in clinical practice. Little is known about dentists' attitudes towards use of the rubber da...

In the present article, effect of non-uniform excitation of reservoir bottom on nonlinear response of concrete gravity dams is considered. Anisotropic damage mechanics approach is used to model nonlinear behavior of mass concrete in 2D space. The tallest monolith of Pine Flat dam is selected as a case study. The horizontal and vertical components of 1967 Koyna earthquake is used to excite the s...

OBJECTIVE Rubber dam is recommended by the British Society of Paediatric Dentistry (BSPD) for various restorative and endodontic procedures. To date, there has been no report of actual usage of rubber dam within the speciality of paediatric dentistry. The aim of this study was to assess the usage of rubber dam amongst paediatric dentistry specialists within the UK. METHODS A postal questionna...

Department of Civil Engineering, University of Colorado Denver, CO 80204, United States b International Research Institute for Climate and Society, The Earth Institute at Columbia University, Palisades, NY 10964, United States Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, United States d Lamont-Doherty Earth Observatory, Columbia University, Palisad...

The khap Tai Dam is the singing of the Tai Dam (or Black Tai) ethnic group. This paper presents the results of an ongoing research studying the relationship between spoken and sung tones in this specific repertoire. Two questions are addressed: (1) Are speech tones realised in khap Tai Dam singing? (2) Are the contours of speech and song similar or different in khap Tai Dam? The main results so...

DNA adenine methylation by DNA adenine methyltransferase (Dam) in Escherichia coli plays an important role in processes such as DNA replication initiation, gene expression regulation, and mismatch repair. In addition, E. coli strains deficient in Dam are hypersensitive to DNA-damaging agents. We used genome microarrays to compare the transcriptional profiles of E. coli strains deficient in Dam ...

T he advantages of using a rubber dam are well-known when performing operative and endodontic procedures. These benefits include the following: disolation of the operating field to keep it dry and clean; dimproved access and visibility; dpotentially improved properties of dental materials; dprotection of the patient and dentist; dimproved operating efficiency. 1 Preparing teeth for indirect res...

Large-scale dams are controversial public infrastructure projects due to the unevenly distributed benefits and losses to local regions. The central government can make redistributive fiscal transfers to attenuate the impacts and reduce the inequality among local governments, but whether large-scale dam projects are Pareto improving is still a question. Using the geographic variation of dam impa...