9,895 research outputs found
Second-chance punitivism and the contractual governance of crime and incivility: New Labour, old Hobbes
The growing application of mechanisms of contractual governance to behaviour that breaches social norms, rather than the criminal law, appears to represent an ethopolitical concern with delinquent self-reform through the activation of technologies of the self. In fact, there is little empirical evidence that the contractual governance of incivility leads to such self-reform. Beneath the ideology of contractual agreement to observe social norms lies what this paper calls a âsecond-chance punitivismâ which operates to crystallise behavioural elements of the Hobbesian social contract, after breach, into a more specific form. The responsibilising and individualising properties of this form of contractual governance set the moral-ideological platform for a retributive punitivism, when the rational agents it creates fail to live up to their image, and are taken to have wasted their âsecond chanceâ
Minimal Mark-Up of multiple choice exams using XML
We describe a minimal XML mark-up for multiple choice exams. In our system, exams may be generated at anytime, by choosing a subset of questions from a pool. Furthermore, the system randomises the order of the choices within each chosen question. Thus a student may sit the exam many times. Our first version of this system has been described elsewhere. In this paper, we discuss the limitations of our first system that led to our current work, and give a description of the new system features, including XML tags for supporting collaborative authoring
Extended radio emission in MOJAVE Blazars: Challenges to Unification
We present the results of a study on the 1.4 GHz kpc-scale radio emission in
the complete flux density limited MOJAVE sample, comprising 135 radio-loud
AGNs. While extended emission is detected in the majority of the sources, about
7% of the sources exhibit only radio core emission. Many BL Lacs exhibit
extended radio power and kpc-scale morphology typical of powerful FRII jets,
while a substantial number of quasars possess radio powers intermediate between
FRIs and FRIIs. This poses challenges to the simple radio-loud unified scheme,
which links BL Lacs to FRIs and quasars to FRIIs. We find a significant
correlation between extended radio emission and pc-scale jet speeds: the more
radio powerful sources possess faster jets. This indicates that the 1.4 GHz (or
low frequency) radio emission is indeed related to jet kinetic power. Various
properties such as extended radio power and apparent pc-scale jet speeds vary
smoothly between different blazar subclasses, suggesting that, at least in
terms of radio jet properties, the distinction between quasars and BL Lac
objects, at an emission-line equivalent width of 5 Angstrom is essentially an
arbitrary one. Based on the assumption that the extended radio luminosity is
affected by the kpc-scale environment, we define the ratio of extended radio
power to absolute optical magnitude as a proxy for environmental effects.
Trends with this parameter suggest that the pc-scale jet speeds and the
pc-to-kpc jet misalignments are not affected by the large-scale environment,
but are more likely to depend upon factors intrinsic to the AGN, or its local
pc-scale environment. We suggest that some of the extremely misaligned MOJAVE
blazar jets could be "hybrid" morphology sources, with an FRI jet on one side
and an FRII jet on the other. (Abridged)Comment: 40 pages, 16 figures, accepted for publication in Ap
Anatomy of helical relativistic jets: The case of S5 0836+710
Helical structures are common in extragalactic jets. They are usually
attributed in the literature to periodical phenomena in the source (e.g.,
precession). In this work, we use VLBI data of the radio-jet in the quasar S5
0836+710 and hypothesize that the ridge-line of helical jets like this
corresponds to a pressure maximum in the jet and assume that the helically
twisted pressure maximum is the result of a helical wave pattern. For our
study, we use observations of the jet in S5 0836+710 at different frequencies
and epochs. The results show that the structures observed are physical and not
generated artificially by the observing arrays. Our hypothesis that the
observed intensity ridge-line can correspond to a helically twisted pressure
maximum is confirmed by our observational tests. This interpretation allows us
to explain jet misalignment between parsec and kiloparsec scales when the
viewing angle is small, and also brings us to the conclusion that
high-frequency observations may show only a small region of the jet flow
concentrated around the maximum pressure ridge-line observed at low
frequencies. Our work provides a potential explanation for the apparent
transversal superluminal speeds observed in several extragalactic jets by means
of transversal shift of an apparent core position with time.Comment: Accepted for publication in the Astrophysical Journa
Ytterbium-doped tantalum pentoxide waveguide lasers
We have demonstrated a Yb:Ta2O5 waveguide laser fabricated by RF magnetron sputtering on oxidised silicon. The waveguide laser was end-pumped with a laser diode at 977 nm and lasing was observed between 1015 and 1020 nm. The launched pump power threshold and slope efficiency were measured to be ~25 mW and 1.78 %, respectively
Chandra & HST Imaging of the Quasars PKS B0106+013 & 3C345: Inverse Compton X-rays and Magnetized Jets
We present results from deep (70 ks) Chandra ACIS observations and Hubble
Space Telescope ACS F475W observations of two highly optically polarized
quasars belonging to the MOJAVE blazar sample, viz., PKS B0106+013 and 1641+399
(3C345). These observations reveal X-ray and optical emission from the jets in
both sources. X-ray emission is detected from the entire length of the 0106+013
radio jet, which shows clear bends or wiggles - the X-ray emission is brightest
at the first prominent kpc jet bend. A picture of a helical kpc jet with the
first kpc-scale bend representing a jet segment moving close(r) to our line of
sight, and getting Doppler boosted at both radio and X-ray frequencies, is
consistent with these observations. The X-ray emission from the jet end however
peaks at about 0.4" (~3.4 kpc) upstream of the radio hot spot. Optical emission
is detected both at the X-ray jet termination peak and at the radio hot spot.
The X-ray jet termination peak is found upstream of the radio hot spot by
around 0.2" (~1.3 kpc) in the short projected jet of 3C345. HST optical
emission is seen in an arc-like structure coincident with the bright radio hot
spot, which we propose is a sharp (apparent) jet bend instead of a terminal
point, that crosses our line of sight and consequently has a higher Doppler
beaming factor. A weak radio hot spot is indeed observed less than 1"
downstream of the bright radio hot spot, but has no optical or X-ray
counterpart. By making use of the pc-scale radio and the kpc-scale radio/X-ray
data, we derive constraints on the jet Lorentz factors (Gamma_jet) and
inclination angles (theta): for a constant jet speed from pc- to kpc-scales, we
obtain a Gamma_jet of ~70 for 0106+013, and ~40 for 3C345. On relaxing this
assumption, we derive a Gamma_jet of ~2.5 for both the sources. Upper limits on
theta of ~13 degrees are obtained for the two quasars. (ABRIDGED)Comment: 46 pages, 11 figures, Accepted for publication in Ap
Governing Global Supply Chain Sustainability Through the Ethical Audit Regime
Over the past two decades multinational corporations have been expanding âethicalâ audit programs with the stated aim of reducing the risk of sourcing from suppliers with poor practices. A wave of government regulationâsuch as the California Transparency in Supply Chains Act (2012) and the UK Modern Slavery Act (2015)âhas enhanced the legitimacy of auditing as a tool to govern labor and environmental standards in global supply chains, backed by a broad range of civil society actors championing audits as a way of promoting corporate accountability. The growing adoption of auditing as a governance tool is a puzzling trend, given two decades of evidence that audit programs generally fail to detect or correct labor and environmental problems in global supply chains. Drawing on original field research, this article shows that in spite of its growing legitimacy and traction among government and civil society actors, the audit regime continues to respond to and protect industry commercial interests. Conceptually, the article challenges prevailing characterizations of the audit regime as a technical, neutral, and benign tool of supply chain governance, and highlights its embeddedness in struggles over the legitimacy and effectiveness of the industry-led privatization of global governance
The connection between the radio jet and the gamma-ray emission in the radio galaxy 3C 120
We present the analysis of the radio jet evolution of the radio galaxy 3C 120
during a period of prolonged gamma-ray activity detected by the Fermi satellite
between December 2012 and October 2014. We find a clear connection between the
gamma-ray and radio emission, such that every period of gamma-ray activity is
accompanied by the flaring of the mm-VLBI core and subsequent ejection of a new
superluminal component. However, not all ejections of components are associated
with gamma-ray events detectable by Fermi. Clear gamma-ray detections are
obtained only when components are moving in a direction closer to our line of
sight.This suggests that the observed gamma-ray emission depends not only on
the interaction of moving components with the mm-VLBI core, but also on their
orientation with respect to the observer. Timing of the gamma-ray detections
and ejection of superluminal components locate the gamma-ray production to
within almost 0.13 pc from the mm-VLBI core, which was previously estimated to
lie about 0.24 pc from the central black hole. This corresponds to about twice
the estimated extension of the broad line region, limiting the external photon
field and therefore suggesting synchrotron self Compton as the most probable
mechanism for the production of the gamma-ray emission. Alternatively, the
interaction of components with the jet sheath can provide the necessary photon
field to produced the observed gamma-rays by Compton scattering.Comment: Already accepted for publication in The Astrophysical Journa
An Extended Radio Counterpart of TeV J2032+4130?
We carried out a 5-pointing mosaic observation of TeV J2032+4130 at 1.4 and
4.8 GHz with the VLA in April of 2003. The analysis of the 4.8GHz data indicate
weak wispy shell-like radio structure(s) which are at least partially
non-thermal. The radio data is compatible with one or more young supernova
remnants or perhaps the signature of large scale cluster shocks in this region
induced by the violent action of the many massive stars in Cyg OB2.Comment: Proc. 1st GLAST Symp. Feb 5-8, 2007, Stanford C
Catching the Radio Flare in CTA 102 III. Core-Shift and Spectral Analysis
The temporal and spatial spectral evolution of the jets of AGN can be studied
with multi-frequency, multi-epoch VLBI observations. The combination of both,
morphological and spectral parameters can be used to derive source intrinsic
physical properties such as the magnetic field and the non-thermal particle
density. In the first two papers of this series, we analyzed the single-dish
light curves and the VLBI kinematics of the blazar CTA 102 and suggested a
shock-shock interaction between a traveling and a standing shock wave as a
possible scenario to explain the observed evolution of the component associated
to the 2006 flare. In this paper we investigate the core-shift and spectral
evolution to test our hypothesis of a shock-shock interaction. We used 8
multi-frequency VLBA observations to analyze the temporal and spatial evolution
of the spectral parameters during the flare. We observed CTA 102 between May
2005 and April 2007 using the VLBA at six different frequencies spanning from 2
- 86 GHz. After the calibrated VLBA images were corrected for opacity, we
performed a detailed spectral analysis. From the derived values we estimated
the magnetic field and the density of the relativistic particles. The detailed
analysis of the opacity shift reveals that the position of the jet core is
proportional to nu^-1 with some temporal variations. The value suggests
possible equipartition between magnetic field energy and particle kinetic
energy densities at the most compact regions. From the variation of the
physical parameters we deduced that the 2006 flare in CTA 102 is connected to
the ejection of a new traveling feature (t=2005.9) and the interaction between
this shock wave and a stationary structure around 0.1 mas from the core. The
source kinematics together with the spectral and structural variations can be
described by helical motions in an over-pressured jet.Comment: 35 pages, 46 figure
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