12 research outputs found
Quaternion-Octonion Analyticity for Abelian and Non-Abelian Gauge Theories of Dyons
Einstein- Schroedinger (ES) non-symmetric theory has been extended to
accommodate the Abelian and non-Abelian gauge theories of dyons in terms of the
quaternion-octonion metric realization. Corresponding covariant derivatives for
complex, quaternion and octonion spaces in internal gauge groups are shown to
describe the consistent field equations and generalized Dirac equation of
dyons. It is also shown that quaternion and octonion representations extend the
so-called unified theory of gravitation and electromagnetism to the Yang-Mill's
fields leading to two SU(2) gauge theories of internal spaces due to the
presence of electric and magnetic charges on dyons
Soil net nitrogen mineralisation across global grasslands
Soil nitrogen mineralisation (Nmin), the conversion of organic into inorganic N, is important
for productivity and nutrient cycling. The balance between mineralisation and immobilisation
(net Nmin) varies with soil properties and climate. However, because most global-scale
assessments of net Nmin are laboratory-based, its regulation under field-conditions and
implications for real-world soil functioning remain uncertain. Here, we explore the drivers of
realised (field) and potential (laboratory) soil net Nmin across 30 grasslands worldwide. We
find that realised Nmin is largely explained by temperature of the wettest quarter, microbial
biomass, clay content and bulk density. Potential Nmin only weakly correlates with realised
Nmin, but contributes to explain realised net Nmin when combined with soil and climatic
variables. We provide novel insights of global realised soil net Nmin and show that potential
soil net Nmin data available in the literature could be parameterised with soil and climate data
to better predict realised NNational Science Foundation Research Coordination Network;
Long-Term Ecological Research;
Institute on the Environment at the University of Minnesota.http://www.nature.com/ncommspm2020Mammal Research InstituteZoology and Entomolog
Author Correction: The messy death of a multiple star system and the resulting planetary nebula as observed by JWST
Stars and planetary system
Development of a Combined Crop and Climate Forecasting System for Seasonal to Decadal Predictions
Adding a second prostaglandin F2α treatment to but not reducing the duration of a PRID-Synch protocol increases fertility after resynchronization of ovulation in lactating Holstein cows
Development of fertility programs to achieve high 21-day pregnancy rates in high-producing dairy cows
On the tracks of the earliest dinosaurs: implications for the hypothesis of dinosaurian monophyly
From the record of dinosaurian skeletal remains it has been inferred that the origin and initial diversification of dinosaurs were rapid events, occupying an interval of about 5 million years in the Late Triassic. By contrast numerous reports of dinosauroid tracks imply that the emergence of dinosaurs was a more protracted affair extending through much of the Early and Middle Triassic. This study finds no convincing evidence of dinosaur tracks before the late Ladinian. Each of the three dinosaurian clades - Theropoda, Sauropodomorpha, Ornithischia - produced a unique track morphotype that appears to be an independent modification of the chirotherioid pattern attributed to stem-group archosaurs (thecodontian reptiles). The existence of three divergent track morphotypes is consistent with the concept of dinosaurian polyphyly but can be reconciled with the hypothesis of dinosaurian monophyly only by invoking many and rapid reversals in the locomotor anatomy of early dinosaurs. The origin of dinosaurs was not the correlate or consequence of any single event or process, be it global change, competitive replacement, or opportunism in the wake of mass extinction. Instead the origin of dinosaurs is envisaged as a series of three cladogenetic events over an interval of at least 10 million years and possibly as much as 25 million years. This scenario of dinosaurian polyphyly is as well-supported by fossil evidence as is the currently favoured view of dinosaurian monophyly