Cosmic Microwave Background Anisotropy Observing Strategy Assessment

I develop a method for assessing the ability of an instrument, coupled with an observing strategy, to measure the angular power spectrum of the cosmic microwave background (CMB). It allows for efficient calculation of expected parameter uncertainties. Related to this method is a means of graphically presenting, via the ``eigenmode window function'', the sensitivity of an observation to different regions of the spectrum, which is a generalization of the traditional practice of presenting the trace of the window function. I apply these techniques to a balloon-borne bolometric instrument to be flown this summer (MSAM2). I find that a smoothly scanning secondary is better than a chopping one and that, in this case, a very simple analytic formula provides a good (40\% or better) approximation to expected power spectrum uncertainties.Comment: Substantial revisions, LaTeX 15 pages including 3 figure

"It isn't just consultants that need a BSc": student experiences of an Intercalated BSc

More medical schools are moving towards a compulsory intercalated BSc. These courses have not traditionally been aimed at those students interested in general practice and have tended to have limited clinical relevance. This paper explores the perceptions of students who undertook a BSc in primary health care using qualitative methodology comprising semi-structured interviews with students just before completion of their course. Interviews were undertaken with 24 of the 26 students who started the course over a 4-year period. All the students have finished the course and have graduated with good honours degrees. Students refine existing skills and develop new, relevant skills for medicine. The students discussed the prestige (or lack) of a BSc in this field and how the course has impacted on their career decisions. A Primary Health Care BSc such as this appears to give students an in depth and to some, a positive view of general practice and primary care. The course allowed students to develop a more critical approach to medicine and enabled them to develop skills in addition to those acquired from their undergraduate medicine course. They perceived that these skills will serve them throughout their career in whatever branch of medicine they choose

Symmetry-enhanced supertransfer of delocalized quantum states

Coherent hopping of excitation rely on quantum coherence over physically extended states. In this work, we consider simple models to examine the effect of symmetries of delocalized multi-excitation states on the dynamical timescales, including hopping rates, radiative decay, and environmental interactions. While the decoherence (pure dephasing) rate of an extended state over N sites is comparable to that of a non-extended state, superradiance leads to a factor of N enhancement in decay and absorption rates. In addition to superradiance, we illustrate how the multi-excitonic states exhibit `supertransfer' in the far-field regime: hopping from a symmetrized state over N sites to a symmetrized state over M sites at a rate proportional to MN. We argue that such symmetries could play an operational role in physical systems based on the competition between symmetry-enhanced interactions and localized inhomogeneities and environmental interactions that destroy symmetry. As an example, we propose that supertransfer and coherent hopping play a role in recent observations of anomolously long diffusion lengths in nano-engineered assembly of light-harvesting complexes.Comment: 6 page

An Absorption Band of Formaldoxime at lambda9572

The third harmonic of the O [Single Bond] H band in formaldoxime vapor has been found to lie at lambda9572 (10,444.1 cm^—1) and under high dispersion has been resolved and found to resemble a parallel band of a symmetric rotator. Owing to the weakness of the lines near the center of the band a definitely unique rotational analysis could not be made but the harmonic mean of the two larger moments of inertia appears to lie between the limits 73.3 and 76.6×10^—40 g cm^2. The hydroxyl hydrogen does not rotate freely and indeed its torsional oscillation appears not to have a very low frequency. It is not possible to locate this hydrogen uniquely until other parameters of the molecule have been determined by electron diffraction. The possible effect of resonance on the O [Single Bond] H frequency is discussed

Structure of the O[Single Bond]H Bands in the Vapors of Halogen Substituted Alcohols

In the study of the infra-red absorption of organic substances containing hydroxyl groups it has been found that the O-H bands sometimes occur as multiplets even though only one such group is present per molecule. This has been observed both in the spectra of vapors (1) and of solutions (2,3) though in the latter case less structure is resolvable in some instances. The phenomenon has been explained by saying that the hydroxyl hydrogen is not free to rotate around the C-O bond, but may be found in more than one position of potential minimum in which the O-H frequency may be somewhat different (1,4). Though this explanation appears plausible it has seemed desirable to investigate the matter further by a quantitative study of some relatively simple substances in the vapor phase. Consequently a series of halogen substituted alcohols has been investigated with interesting results

Care of Nursery Stock in Retail Outlets

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Information, information processing and gravity

I discuss fundamental limits placed on information and information processing by gravity. Such limits arise because both information and its processing require energy, while gravitational collapse (formation of a horizon or black hole) restricts the amount of energy allowed in a finite region. Specifically, I use a criterion for gravitational collapse called the hoop conjecture. Once the hoop conjecture is assumed a number of results can be obtained directly: the existence of a fundamental uncertainty in spatial distance of order the Planck length, bounds on information (entropy) in a finite region, and a bound on the rate of information processing in a finite region. In the final section I discuss some cosmological issues related to the total amount of information in the universe, and note that almost all detailed aspects of the late universe are determined by the randomness of quantum outcomes. This paper is based on a talk presented at a 2007 Bellairs Research Institute (McGill University) workshop on black holes and quantum information.Comment: 7 pages, 5 figures, revte

The Extent of the Spectral Bias in BATSE: The True Distribution of the nu F_nu Peak Energy

The distributions of spectral characteristics and their correlations with fluence, peak flux, or duration, are essential in understanding the nature of GRBs. However, the selection effects involved in detecting GRBs can distort these distributions. Here, we discuss how to deal with selection effects involving the peak energy E_p of the GRB nu F_nu spectrum, which suffers from both an upper and lower threshold. We describe a new method to account for this double-sided truncation, and show that the true distribution of E_p is significantly different from the observed distribution.Comment: 5 pages, 3 postscript figures. To appear in the proceedings of the 4th Huntsville Gamma Ray Burst Symposium, C.A.Meegan, P.Cushman, ed

On the Kinetic Energy and Radiative Efficiency of Gamma-Ray Bursts

Using measured X-ray luminosities to 17 Gamma-Ray Bursts (GRBs) during the afterglow phase and accounting for radiative losses, we calculate the kinetic energy of these bursts and investigate its relation to other GRB properties. We then use the observed radiated energy during the prompt phase to determine the radiative efficiency of these bursts, and explore how the efficiency relates to other GRB observables. We find that the kinetic energy in the afterglow phase is directly correlated with the radiated energy, total energy as well as possibly the jet opening angle and spectral peak energy. More importantly, we find the intriguing fact that the efficiency is correlated with the radiated energy, and mildly with the total energy, jet opening angle and spectral peak energy. XRF020903 also seems to follow the trends we find for our GRB sample. We discuss the implications of these results for the GRB radiation and jet models.Comment: 9 pages, 7 figures; Revised version, accepted to Ap