15,338 research outputs found
Rippled Cosmological Dark Matter from Damped Oscillating Newton Constant
Let the reciprocal Newton 'constant' be an apparently non-dynamical
Brans-Dicke scalar field damped oscillating towards its General Relativistic
VEV. We show, without introducing additional matter fields or dust, that the
corresponding cosmological evolution averagely resembles, in the Jordan frame,
the familiar dark radiation -> dark matter -> dark energy domination sequence.
The fingerprints of our theory are fine ripples, hopefully testable, in the FRW
scale factor; they die away at the General Relativity limit. The possibility
that the Brans-Dicke scalar also serves as the inflaton is favorably examined.Comment: RevTex4, 12 pages, 5 figures; Minor revision, References adde
Preparation of Cu-based bulk metallic glasses by suction casting
A series of Cu-Hf-Ti alloys prepared by rapid solidification of the melt and by copper mould casting were studied in the present work. Alloy ingots were prepared by arc-melting mixtures of pure metals in an argon atmosphere. An indication of the cooling rate obtained was determined using an Al-4.5 wt%Cu alloy. Cooling rates varied from 540 K/s for the centre section of a 4 mm die to 885 K/s for the outside wall section of the 2 mm die. The glass-forming ability, structure and thermal stability of Cu-Hf-Ti glassy alloys were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Bulk glass formation was observed for the Cu64Hf36, Cu55Hf25Ti20 and Cu56Hf25Ti19 alloys, with critical diameters dc for a fully glassy structure of 1, 4 and 5 mm, respectively. The substitution of Hf by Ti increased the glassforming ability (GFA) and the thermal stability
A head restraint device for vestibular studies
Head restraint device based on vacuum bladder technique for use in vestibular studie
Sigma-Model Aether
Theories of low-energy Lorentz violation by a fixed-norm "aether" vector
field with two-derivative kinetic terms have a globally bounded Hamiltonian and
are perturbatively stable only if the vector is timelike and the kinetic term
in the action takes the form of a sigma model. Here we investigate the
phenomenological properties of this theory. We first consider the propagation
of modes in the presence of gravity, and show that there is a unique choice of
curvature coupling that leads to a theory without superluminal modes.
Experimental constraints on this theory come from a number of sources, and we
examine bounds in a two-dimensional parameter space. We then consider the
cosmological evolution of the aether, arguing that the vector will naturally
evolve to be orthogonal to constant-density hypersurfaces in a
Friedmann-Robertson-Walker cosmology. Finally, we examine cosmological
evolution in the presence of an extra compact dimension of space, concluding
that a vector can maintain a constant projection along the extra dimension in
an expanding universe only when the expansion is exponential.Comment: 8 pages, 2 figures; fixed minor typo and changed references in v
An attempt to predict critical incident categories from three personality variables
M.S.William W. Rona
Variables to Predict Risk of Hospital Readmission
As the healthcare industry transitions toward accountable care and payment reform, creative approaches to healthcare is imperative. Poorly coordinated care and shorter hospital stays have resulted in higher rates of readmissions. This has large implications for hospitals and health systems
Arterial Mycotic Aneurysm and Rupture: A Potentially Fatal Complication of Pancreas Transplantation in Diabetes Mellitus
• Mycotic aneurysm at the site of a Carrel patch arterial anastomosis occurred in four patients who had undergone whole pancreas transplantation 2.5 to 14.5 months previously. In all patients, the graft had been removed, leaving the Carrel patch on the iliac artery. The aneurysms ruptured into the intestine or the extraperitoneal space. The ruptures were sudden and life-threatening in three of four cases. This diagnosis must be suspected in patients with a history of pancreas transplantation in the immediate or distant past if they present with unexplained hypotension, cardiac arrest, or gastrointestinal tract bleeding. © 1989, American Medical Association. All rights reserved
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