Letter from P. A. Doran to John Muir, 1903 Apr 21

San Francisco April 21st 1903 Professor John Muir. Martinez My Dear Professor Leaving here Thursday morning next with the Columbia will be my last trip for some time, and I go east from Portland, and possibly heave to in Europe/ Mrs. Doran will be accompanying me. I intended calling on you last month, but the annual drydocking and overhauling threw us so far behind thime that it looks nearly like the whole month to catch our old schedule. And this month Mrs. Doran has been busy preparing for our journey. I am sorry I canΓÇÖt see Helen before I leave, as I have some huge stories of our friends the ΓÇ£Huge Levithians of the deep.ΓÇ¥ But I will expect to see some on the Atlantic and will tell her all about them when I return. Mrs. Doran joins me in kindest regards to yourself and your family. Wishing you a successful voyage and that you may discover several new ΓÇ£Huge LeviathasrsΓÇ¥ I am Sincerely yours P. A. Doran S.S. Columbi

Letter from P. A. Doran to John Muir, 1901 Dec 21.

San Francisco Dec 21st, 1901.Professor John Muir,Martinez,My dear Professor,I beg to acknowledge receipt of you new book for which I thank you. I shall take it with me this voyage, and have the pleasure of a stroll through the forests while on the dark blue. Trusting you are all well, and with kindest regards to Wanda and Helen, and best wishes for a Happy New Year I amRespectfully yoursP. A. Doran.2110 Union St.0290

Letter from P. A. Doran to John Muir, 1905 Sep 28.

[letterhead]S. S. Columbia Sept. 28, 1905My dear Professor Muir,I am very much pleased to know that Helen is improving and hope, for your sake as well as her own, she will continue so and grow entirely well.I wish I could prescribe for her with the same success as in your case. However, when she is again well and strong, I would recommend a trip on the Columbia, and I shall arrange matters with old ocean, and ours esteemed friends the huge leviathans, for a pleasant voyage.Trusting this will find you in good health and confidence regarding Helen\u27s speedy recover I amYours very truly, P. A. Dorans. S. ColumbiaSpear St. WharfS. F.0363

Letter from P. A. Doran to John Muir, 1899 Sep 8.

san Francisco Sept 8th, 99.Professor John Muir,Martinez, Cal.My Dear Professor; I received your book and many thanks to you. I can see your many characteristics throughout the work, and every page reminds me of the pleasant hours spent together during our voyage to Alaska. To say the least it is a noble and interesting work, and we are all delighted with it. I forward you a copy of the H.A.E. poems. I would have send them before but I was called to Portland unexpectedly, to take command of S.S. Columbia . Should you contemplate a trip to Portland, I would be very pleased to have you come on the Columbia , and I promise you our morning coffee shall be the best.Hoping we will be shipmates again in the near future and commemorate the 02619 H.A.E. by sliding over a few glaciers Slivers I am Yours very respectfullyP.A. DoranS.S. ColumbiaSan Francisco0261

Women's mountaineering tourism::an empirical investigation of its theoretical constraint dimensions

The purpose of this study is to investigate the perceived constraints on participating in mountaineering tourism faced by women, and to empirically verify the dimensionality of those constraints. Survey responses from 314 female mountaineers were collected and four constraint dimensions were identified using confirmatory factor analysis. Three of these dimensions: 'intra-personal', 'inter-personal' and 'structural' constraints support earlier findings in the extant literature, both in general and in the adventure literature more specifically. The identification of a fourth dimension relating to 'family' constraints represents a theoretical contribution to the literature and an additional barrier to women's participation in mountaineering tourism. In previous studies, ‘family’ constraints have typically been subsumed within ‘inter-personal’ or 'intra-personal' constraints, but have emerged as a distinctly separate constraint category for women in relation to this particular tourist activity. The findings also have important implications for adventure tourism management practice

Fermion absorption cross section of a Schwarzschild black hole

We study the absorption of massive spin-half particles by a small Schwarzschild black hole by numerically solving the single-particle Dirac equation in Painleve-Gullstrand coordinates. We calculate the absorption cross section for a range of gravitational couplings Mm/m_P^2 and incident particle energies E. At high couplings, where the Schwarzschild radius R_S is much greater than the wavelength lambda, we find that the cross section approaches the classical result for a point particle. At intermediate couplings we find oscillations around the classical limit whose precise form depends on the particle mass. These oscillations give quantum violations of the equivalence principle. At high energies the cross section converges on the geometric-optics value of 27 \pi R_S^2/4, and at low energies we find agreement with an approximation derived by Unruh. When the hole is much smaller than the particle wavelength we confirm that the minimum possible cross section approaches \pi R_S^2/2.Comment: 11 pages, 3 figure

Varying Alpha Monopoles

We study static magnetic monopoles in the context of varying alpha theories and show that there is a group of models for which the t'Hooft-Polyakov solution is still valid. Nevertheless, in general static magnetic monopole solutions in varying alpha theories depart from the classical t'Hooft-Polyakov solution with the electromagnetic energy concentrated inside the core seeding spatial variations of the fine structure constant. We show that Equivalence Principle constraints impose tight limits on the allowed variations of alpha induced by magnetic monopoles which confirms the difficulty to generate significant large-scale spatial variation of the fine structure constant found in previous works. This is true even in the most favorable case where magnetic monopoles are the source for these variations.Comment: 8 pages, 10 figures; Version to be published in Phys. Rev.

Early Dark Energy Cosmologies

We propose a novel parameterization of the dark energy density. It is particularly well suited to describe a non-negligible contribution of dark energy at early times and contains only three parameters, which are all physically meaningful: the fractional dark energy density today, the equation of state today and the fractional dark energy density at early times. As we parameterize Omega_d(a) directly instead of the equation of state, we can give analytic expressions for the Hubble parameter, the conformal horizon today and at last scattering, the sound horizon at last scattering, the acoustic scale as well as the luminosity distance. For an equation of state today w_0 < -1, our model crosses the cosmological constant boundary. We perform numerical studies to constrain the parameters of our model by using Cosmic Microwave Background, Large Scale Structure and Supernovae Ia data. At 95% confidence, we find that the fractional dark energy density at early times Omega_early < 0.06. This bound tightens considerably to Omega_early < 0.04 when the latest Boomerang data is included. We find that both the gold sample of Riess et. al. and the SNLS data by Astier et. al. when combined with CMB and LSS data mildly prefer w_0 < -1, but are well compatible with a cosmological constant.Comment: 6 pages, 3 figures; references added, matches published versio

Painleve-Gullstrand Coordinates for the Kerr Solution

We construct a coordinate system for the Kerr solution, based on the zero angular momentum observers dropped from infinity, which generalizes the Painleve-Gullstrand coordinate system for the Schwarzschild solution. The Kerr metric can then be interpreted as describing space flowing on a (curved) Riemannian 3-manifold. The stationary limit arises as the set of points on this manifold where the speed of the flow equals the speed of light, and the horizons as the set of points where the radial speed equals the speed of light. A deeper analysis of what is meant by the flow of space reveals that the acceleration of free-falling objects is generally not in the direction of this flow. Finally, we compare the new coordinate system with the closely related Doran coordinate system.Comment: 6 pages; v2: new section, matches final published version; v3: sign error in the expression of the function delta correcte

New Techniques for Analysing Axisymmetric Gravitational Systems. 1. Vacuum Fields

A new framework for analysing the gravitational fields in a stationary, axisymmetric configuration is introduced. The method is used to construct a complete set of field equations for the vacuum region outside a rotating source. These equations are under-determined. Restricting the Weyl tensor to type D produces a set of equations which can be solved, and a range of new techniques are introduced to simplify the problem. Imposing the further condition that the solution is asymptotically flat yields the Kerr solution uniquely. The implications of this result for the no-hair theorem are discussed. The techniques developed here have many other applications, which are described in the conclusions.Comment: 30 pages, no figure