3,415 research outputs found
'The world is full of big bad wolves': investigating the experimental therapeutic spaces of R.D. Laing and Aaron Esterson
In conjunction with the recent critical assessments of the life and work of R.D. Laing, this paper seeks to demonstrate what is revealed when Laingâs work on families and created spaces of mental health care are examined through a geographical lens. The paper begins with an exploration of Laingâs time at the Tavistock Clinic in London during the 1960s, and of the co-authored text with Aaron Esterson entitled, Sanity, Madness and the Family (1964). The study then seeks to demonstrate the importance Laing and his colleague placed on the time-space situatedness of patients and their worlds. Finally, an account is provided of Laingâs and Estersonâs spatial thinking in relation to their creation of both real and imagined spaces of therapeutic care
Survival of thermophilic spore-forming bacteria in a 90+ year old milk powder from Ernest Shackelton's Cape Royds Hut in Antarctica
Milk powder taken to Antarctica on Shackelton's British Antarctic Expedition in 1907 was produced in New Zealand by a roller drying process in the first factory in the world dedicated to this process. Thermophilic bacilli are the dominant contaminants of modern spray-dried milk powders and the 1907 milk powder allows a comparison to be made of contaminating strains in roller-dried and spray-dried powders. Samples of milk powder obtained from Shackelton's Hut at Cape Royds had low levels of thermophilic contamination (<500 cfu mlâ1) but the two dominant strains (Bacillus licheniformis strain F and Bacillus subtilis) were typical of those found in spray-dried powders. Soil samples from the floor of the hut also contained these strains, whereas soils distant from the hut did not. Differences in the RAPD profiles of isolates from the milk powder and the soils suggest that contamination of the milk from the soil was unlikely. It is significant that the most commonly encountered contaminant strain in modern spray-dried milk (Anoxybacillus flavithermus strain C) was not detected in the 1907 sample
An Attempt to Probe the Radio Jet Collimation Regions in NGC 4278, NGC 4374 (M84), and NGC 6166
NRAO Very Long Baseline Array (VLBA) observations of NGC 4278, NGC 4374
(M84), NGC 6166, and M87 (NGC 4486) have been made at 43 GHz in an effort to
image the jet collimation region. This is the first attempt to image the first
three sources at 43 GHz using Very Long Baseline Interferometry (VLBI)
techniques. These three sources were chosen because their estimated black hole
mass and distance implied a Schwarzschild radius with large angular size,
giving hope that the jet collimation regions could be studied. Phase
referencing was utilize for the three sources because of their expected low
flux densities. M87 was chosen as the calibrator for NGC 4374 because it
satisfied the phase referencing requirements: nearby to the source and
sufficiently strong. Having observed M87 for a long integration time, we have
detected its sub-parsec jet, allowing us to confirm previous high resolution
observations made by Junor, Biretta & Livio, who have indicated that a wide
opening angle was seen near the base of the jet. Phase referencing successfully
improved our image sensitivity, yielding detections and providing accurate
positions for NGC 4278, NGC 4374 and NGC 6166. These sources are point
dominated, but show suggestions of extended structure in the direction of the
large-scale jets. However, higher sensitivity will be required to study their
sub-parsec jet structure
Energy Injection Episodes in Gamma Ray Bursts: The Light Curves and Polarization Properties of GRB 021004
Several GRB afterglow light curves deviate strongly from the power law decay
observed in most bursts. We show that these variations can be accounted for by
including refreshed shocks in the standard fireball model previously used to
interpret the overall afterglow behavior. As an example we consider GRB 021004
that exhibited strong light curve variations and has a reasonably well
time-resolved polarimetry. We show that the light curves in the R-band, X-rays
and in the radio can be accounted for by four energy injection episodes in
addition to the initial event. The polarization variations are shown to be a
consequence of the injections.Comment: 4 pages, 2 figures. To appear in ApJ
Relativistic Landau damping of longitudinal waves in isotropic pair plasmas
Landau damping is described in relativistic electron-positron
plasmas. Relativistic electron-positron plasma theory contains
important new effects when compared with classical plasmas. For
example, there are undamped superluminal wave modes arising from
both a continuous and discrete mode structure, the former even in
the classical limit. We present here a comprehensive analytical
treatment of the general case resulting in a compact and useful
form for the dispersion relation. The classical pair-plasma case
is addressed, for completeness, in an appendix
Polarization in the prompt emission of gamma-ray bursts and their afterglows
Synchrotron is considered the dominant emission mechanism in the production
of gamma-ray burst photons in the prompt as well as in the afterglow phase.
Polarization is a characteristic feature of synchrotron and its study can
reveal a wealth of information on the properties of the magnetic field and of
the energy distribution in gamma-ray burst jets. In this paper I will review
the theory and observations of gamma-ray bursts polarization. While the theory
is well established, observations have prove difficult to perform, due to the
weakness of the signal. The discriminating power of polarization observations,
however, cannot be overestimated.Comment: 16 pages, 9 figures, accepted for publication in the New Journal of
Physics focus issue on Gamma Ray Burst
Ultra-relativistic electrostatic Bernstein waves
A new general form of the dispersion relation for electrostatic Bernstein waves in ultra-relativistic pair plasmas, characterized by aâ1 = kBT/(mec2)  1, is derived in this paper. The parameter Sp = aΩ0/Ïp, where Ω0 is the rest cyclotron frequency for electrons or positrons and Ïp is the electron (or positron) plasma frequency, plays a crucial role in characterizing these waves. In particular, Sp has a restricted range for permitted wave solutions; this range is effectively unlimited for classical plasmas, but is significant for the ultra-relativistic case. The characterization of these waves is applied in particular to the presence of such plasmas in pulsar atmospheres
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