1,514 research outputs found
Medical Malpractice Suits: A Physician\u27s Primer for Defendants
This paper is a primer for physicians and their counsel, outlining ways of avoiding a malpractice suit and what to expect in court. My first county medical society appointment in 1912 was as chairman of the legislative committee, and in the years intervening I have had wide experience advising doctors, helping defense attorneys, appearing in court many times as an expert witness, and as a defendant. So I speak from experience. The suggestions as to technique are, in the main, from the recordsm of three cases (containing photostatic copies of all office and hospital records, pyelograms, detective reports, etc.), loaned by a malpractice insurance company
A search for high redshift clusters associated with radio galaxies at 2 < z < 4
High redshift radio galaxies are amongst the most massive galaxies in the
early Universe and have properties expected from central galaxies in forming
clusters. We are carrying out an observational programme on the VLT to find and
study galaxy proto clusters around radio galaxies at redshifts 2 < z < 4.
First, we use narrow band imaging to select candidate galaxies which show
excess Lyman alpha emission at redshifts similar to the central radio galaxy.
Then, we use multi object spectroscopy to confirm the redshifts of these
candidates and measure the velocity dispersion of the cluster members. Our goal
is to observe a sample of about 10 targets and investigate galaxy overdensities
as a function of redshift. Here, we report on the current progress of the
programme and show some preliminary results which include the discovery of a
structure of galaxies at redshift 4.1.Comment: 4 pages, 3 figures, Sesto conference proceeding 'Probing cosmic
evolution with galaxy clusters
A new luminosity component in 3C 48
The infrared emission from the quasar 3C 48 has a luminosity L â 5 x 10^(12) L_â and dominates the power output of the quasar system. It is shown that the infrared emission, unlike that of most radio-loud quasars, is most likely not an extension of the radio emission of the quasar. It is argued that the infrared emission in 3C 48 is probably thermal radiation arising in a highly luminous galaxy surrounding the quasar
Ultra Low Momentum Neutron Catalyzed Nuclear Reactions on Metallic Hydride Surfaces
Ultra low momentum neutron catalyzed nuclear reactions in metallic hydride
system surfaces are discussed. Weak interaction catalysis initially occurs when
neutrons (along with neutrinos) are produced from the protons which capture
``heavy'' electrons. Surface electron masses are shifted upwards by localized
condensed matter electromagnetic fields. Condensed matter quantum
electrodynamic processes may also shift the densities of final states allowing
an appreciable production of extremely low momentum neutrons which are thereby
efficiently absorbed by nearby nuclei. No Coulomb barriers exist for the weak
interaction neutron production or other resulting catalytic processes.Comment: 4 pages, ReVTeX forma
A study of distant Ly-alpha emitters in overdense regions
Recently, we conducted a Very Large Telescope (VLT) large program to search
for forming clusters by looking for overdensities of Ly-alpha emitters around
high redshift radio galaxies. In total seven proto-clusters were discovered,
including a proto-cluster around the radio galaxy MRC 0316--257 at z ~ 3.13.
This structure has an excess of Ly-alpha emitters by a factor of 3 as compared
to the field, and the derived mass is 2-5 x 10^14 M_sun. The Ly-alpha emitters
in the proto-cluster are on average bluer than Lyman Break Galaxies (LBGs).
Also, the galaxies are faint (sub L_*) and small (half light radii < 1.7 kpc,
which is smaller than the average size of LBGs). This might indicate that, at
least a fraction of, Ly-alpha emitters could be young (~ 10^6 yr), nearly
dust-free, forming galaxies.Comment: 6 pages, 2 figures. To appear in the proceedings of the Venice
conference "Multiwavelength Mapping of Galaxy Formation and Evolution",
October 13-16, 200
A new sample of faint Gigahertz Peaked Spectrum radio sources
The Westerbork Northern Sky Survey (WENSS) has been used to select a sample
of Gigahertz Peaked Spectrum (GPS) radio sources at flux densities one to two
orders of magnitude lower than bright GPS sources investigated in earlier
studies. Sources with inverted spectra at frequencies above 325 MHz have been
observed with the WSRT at 1.4 and 5 GHz and with the VLA at 8.6 and 15 GHz to
select genuine GPS sources. This has resulted in a sample of 47 GPS sources
with peak frequencies ranging from ~500 MHz to >15 GHz, and peak flux densities
ranging from ~40 to ~900 mJy. Counts of GPS sources in our sample as a function
of flux density have been compared with counts of large scale sources from
WENSS scaled to 2 GHz, the typical peak frequency of our GPS sources. The
counts can be made similar if the number of large scale sources at 2 GHz is
divided by 250, and their flux densities increase by a factor of 10. On the
scenario that all GPS sources evolve into large scale radio sources, these
results show that the lifetime of a typical GPS source is ~250 times shorter
than a typical large scale radio source, and that the source luminosity must
decrease by a factor of ~10 in evolving from GPS to large scale radio source.
However, we note that the redshift distributions of GPS and large scale radio
sources are different and that this hampers a direct and straightforward
interpretation of the source counts. Further modeling of radio source evolution
combined with cosmological evolution of the radio luminosity function for large
sources is required.Comment: LaTeX, 15 pages, 8 figs. To be published in A&AS. For more info see
http://www.ast.cam.ac.uk/~snelle
The MURALES survey II. Presentation of MUSE observations of 20 3C low-z radio galaxies and first results
We present observations of a complete sub-sample of 20 radio galaxies from
the Third Cambridge Catalog (3C) with redshift <0.3 obtained from VLT/MUSE
optical integral field spectrograph. These data have been obtained as part of
the survey MURALES (a MUse RAdio Loud Emission line Snapshot survey) with the
main goal of exploring the Active Galactic Nuclei (AGN) feedback process in a
sizeable sample of the most powerful radio sources at low redshift. We present
the data analysis and, for each source, the resulting emission line images and
the 2D gas velocity field. Thanks to their unprecedented depth (the median 3
sigma surface brightness limit in the emission line maps is 6X10^-18 erg s-1
cm-2 arcsec-2, these observations reveal emission line structures extending to
several tens of kiloparsec in most objects. In nine sources the gas velocity
shows ordered rotation, but in the other cases it is highly complex. 3C sources
show a connection between radio morphology and emission line properties.
Whereas, in three of the four Fanaroff and Riley Class I radio galaxies (FRIs),
the line emission regions are compact, ~1 kpc in size; in all but one of the
Class II radiogalaxies FRIIs, we detected large scale structures of ionized gas
with a median extent of 17 kpc. Among the FRIIs, those of high and low
excitation show extended gas structures with similar morphological properties,
suggesting that they both inhabit regions characterized by a rich gaseous
environment on kpc scale.Comment: Accepted for publication in A&
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