515,815 research outputs found
Advice to a Princess: the literary articulation of a religious, political and cultural programme for Mary Queen of Scots, 1562
No abstract available
Muskrats on tidal marshes of Dorchester County
This bulletin reports, in a non-technical manner, investigations on the Virginia muskrat, prevalent in Maryland, from July, 1949 to June, 1951
Coteries, commendatory verse and Jacobean poetics: William Fowler's Triumphs of Petrarke and its Castalian circles
The Renaissance uses of a medieval Seneca: murder, stoicism, and gender in the marginalia of Glasgow Hunter 297
Examines, transcribes, and annotates the extensive marginalia in a medieval manuscript of Seneca\u27s tragedies made by Sir William Sinclair of Mey (1582-1643), exploring some of the links between the original text, the marginal additions, the events of Sinclair\u27s life, and the culture of Renaissance Scotland
Absolute Time Derivatives
A four dimensional treatment of nonrelativistic space-time gives a natural
frame to deal with objective time derivatives. In this framework some well
known objective time derivatives of continuum mechanics appear as
Lie-derivatives. Their coordinatized forms depends on the tensorial properties
of the relevant physical quantities. We calculate the particular forms of
objective time derivatives for scalars, vectors, covectors and different second
order tensors from the point of view of a rotating observer. The relation of
substantial, material and objective time derivatives is treated.Comment: 26 pages, 4 figures (minor revision
Fine strand-like structure in the solar corona from MHD transverse oscillations
Current analytical and numerical modelling suggest the existence of
ubiquitous thin current sheets in the corona that could explain the observed
heating requirements. On the other hand, new high resolution observations of
the corona indicate that its magnetic field may tend to organise itself in fine
strand-like structures of few hundred kilometres widths. The link between small
structure in models and the observed widths of strand-like structure several
orders of magnitude larger is still not clear. A popular theoretical scenario
is the nanoflare model, in which each strand is the product of an ensemble of
heating events. Here, we suggest an alternative mechanism for strand
generation. Through forward modelling of 3D MHD simulations we show that small
amplitude transverse MHD waves can lead in a few periods time to strand-like
structure in loops in EUV intensity images. Our model is based on previous
numerical work showing that transverse MHD oscillations can lead to
Kelvin-Helmholtz instabilities that deform the cross-sectional area of loops.
While previous work has focused on large amplitude oscillations, here we show
that the instability can occur even for low wave amplitudes for long and thin
loops, matching those presently observed in the corona. We show that the
vortices generated from the instability are velocity sheared regions with
enhanced emissivity hosting current sheets. Strands result as a complex
combination of the vortices and the line-of-sight angle, last for timescales of
a period and can be observed for spatial resolutions of a tenth of loop radius.Comment: Accepted for publication in ApJ
On Rotations as Spin Matrix Polynomials
Recent results for rotations expressed as polynomials of spin matrices are
derived here by elementary differential equation methods. Structural features
of the results are then examined in the framework of biorthogonal systems, to
obtain an alternate derivation. The central factorial numbers play key roles in
both derivations.Comment: 6 Figures. References updated in v2, along with some editing of tex
- …