نتایج جستجو برای: all apparently began ca 5 2 ma
تعداد نتایج: 4519419 فیلتر نتایج به سال:
A worker ant preserved with microscopic detail has been discovered in Turonian-aged New Jersey amber [ca. 92 mega-annum (Ma)]. The apex of the gaster has an acidopore and, thus, allows definitive assignment of the fossil to the large extant subfamily Formicinae, members of which use a defensive spray of formic acid. This specimen is the only Cretaceous record of the subfamily, and only two othe...
Competing end-member models for the late Paleozoic Variscan orogeny (ca. 360-290 Ma) alternatively suggest moderate 2–3 km elevations underlain by relatively thin crust (<50 km) or a thick (>55 that supported high 4–5 elevations. We tested these and quantified crustal thickness elevation evolution of using igneous trace element geochemical proxies geochronologic data. These data (55–70 capable ...
1. Panorama Research Institute and Velocity Pharmaceutical Development; South San Francisco, CA USA; 2. EnGen Bio, Inc.; San Mateo, CA USA; 3. Simon Fraser University; Burnaby, BC Canada; 4. Genmab; Utrecht, the Netherlands; 5. Leiden University Medical Center, Leiden, the Netherlands; 6. The Scripps Research Institute; La Jolla, CA USA; 7. Los Alamos National Laboratory; Los Alamos, NM USA 8. ...
OXIDES/OXYHYDROXIDES: CLUES TO SURFACE ALTERATION AND AQUEOUS PROCESSES. J. L. Bishop 1 , M. D. Dyar 2 , M. Parente 3 , A. Drief 4 , R. L. Mancinelli 1 , M. D. Lane 5 and E. Murad 6 . 1 SETI Institute/NASA-ARC, Mountain View, CA, 2 Mount Holyoke College, South Hadley, MA, 3 Electrical Engineering, Stanford Univ., Stanford, CA, 4 Asbestos TEM Lab. Inc, Berkeley, CA., 5 Planetary Science Institut...
Although the crucial function of earthworms in improvement of soil physical properties is well -know, but very little is known of the interactive influence of earthworms and organic materials on soil properties such as soil aggregate stability, particularly in arid and semi-arid soils. The low organic matter content and the significant role of earthworms in improving physical properties of arid...
Mice expressing the human Cu(2+)/Zn(2+) superoxide dismutase 1 (hSOD1) gene mutation (hSOD1(G93A); G93A) were exposed to methylmercury (MeHg) at concentrations that did not cause overt motor dysfunction. We hypothesized that low concentrations of MeHg could hasten development of the amyotrophic lateral sclerosis (ALS)-like phenotype in G93A mice. MeHg (1 or 3 ppm/day in drinking water) concentr...
Karthik Shekhar, 2 Claire F. Ruberman, Andrew L. Ferguson, John P. Barton, 2 Mehran Kardar, ∗ and Arup K. Chakraborty 5, 6, 7, 8, † Department of Chemical Engineering, MIT, Cambridge, MA 02139 Ragon Institute of MGH, MIT and Harvard, Boston, MA 02129 Department of Mathematics, Pomona College, Claremont, CA 91711 Department of Materials Science and Engineering, University of Illinois at Urbana-C...
The linking of North and South America by the Isthmus of Panama had major impacts on global climate, oceanic and atmospheric currents, and biodiversity, yet the timing of this critical event remains contentious. The Isthmus is traditionally understood to have fully closed by ca. 3.5 million years ago (Ma), and this date has been used as a benchmark for oceanographic, climatic, and evolutionary ...
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