797 research outputs found
Tiered Technologies of Power: Subject-making in China through Electronic Censorship
Since its inception and rise to wide-spread popularity, the internet has provided new opportunities for communication and configured global connectivity possibilities and information sharing. However, with this technological revolution, new and interesting regulatory challenges have emerged. With this paper, I build on Foucauldian understandings of governmentality to examine internet censorship in China within the global context, arguing that these issues of internet censorship in China represent an important example of the emergence of new techniques of governing that stem from new, globalized threats to state control. As a fundamentally global network, the internet ranks among one of the most pressing of these threats, requiring new regulatory practices in both authoritarian and non-authoritarian regimes. This paper argues that as a result, new, decentralized regulatory practices have emerged to augment existing centralized techniques of control and, in the process, constructed tiered technologies of power through which subjects are produced and governed
Probability of Tropical Cyclone Induced Winds at Cape Kennedy
A statistical technique is developed for estimating the climatological probability that an existing tropical cyclone will produce sustained 35-knot winds at Cape Kennedy. Probabilities are specified for specific times and for various time intervals extending to seven days. The technique is developed initially considering only the storm\u27s location, then expanded to take into account its antecedent path. Two classes of storms are processed separately: (1) Those originating over the Atlantic Ocean or the eastern Caribbean Sea, and (2) those originating over the western Caribbean Sea or the Gulf of Mexico. The technique can be adapted for wind speeds of other threshold values and for other coastal locations which may be affected by tropical cyclones
Modelling the hepatitis B vaccination programme in prisons
A vaccination programme offering hepatitis B (HBV) vaccine at reception into prison has been introduced into selected prisons in England and Wales. Over the coming years it is anticipated this vaccination programme will be extended. A model has been developed to assess the potential impact of the programme on the vaccination coverage of prisoners, ex-prisoners, and injecting drug users (IDUs). Under a range of coverage scenarios, the model predicts the change over time in the vaccination status of new entrants to prison, current prisoners and IDUs in the community. The model predicts that at baseline in 2012 57% of the IDU population will be vaccinated with up to 72% being vaccinated depending on the vaccination scenario implemented. These results are sensitive to the size of the IDU population in England and Wales and the average time served by an IDU during each prison visit. IDUs that do not receive HBV vaccine in the community are at increased risk from HBV infection. The HBV vaccination programme in prisons is an effective way of vaccinating this hard-to-reach population although vaccination coverage on prison reception must be increased to achieve this
Resonance fluorescence in a band gap material: Direct numerical simulation of non-Markovian evolution
A numerical method of calculating the non-Markovian evolution of a driven
atom radiating into a structured continuum is developed. The formal solution
for the atomic reduced density matrix is written as a Markovian algorithm by
introducing a set of additional, virtual density matrices which follow, to the
level of approximation of the algorithm, all the possible trajectories of the
photons in the electromagnetic field. The technique is perturbative in the
sense that more virtual density matrices are required as the product of the
effective memory time and the effective coupling strength become larger. The
number of density matrices required is given by where is the number
of timesteps per memory time. The technique is applied to the problem of a
driven two-level atom radiating close to a photonic band gap and the
steady-state correlation function of the atom is calculated.Comment: 14 pages, 9 figure
The steady state quantum statistics of a non-Markovian atom laser
We present a fully quantum mechanical treatment of a single-mode atomic
cavity with a pumping mechanism and an output coupling to a continuum of
external modes. This system is a schematic description of an atom laser. In the
dilute limit where atom-atom interactions are negligible, we have been able to
solve this model without making the Born and Markov approximations. When
coupling into free space, it is shown that for reasonable parameters there is a
bound state which does not disperse, which means that there is no steady state.
This bound state does not exist when gravity is included, and in that case the
system reaches a steady state. We develop equations of motion for the two-time
correlation in the presence of pumping and gravity in the output modes. We then
calculate the steady-state output energy flux from the laser.Comment: 14 pages (twocloumn), 6 figure
Nosocomial transmission of C. difficile in English hospitals from patients with symptomatic infection.
BACKGROUND: Recent evidence suggests that less than one-quarter of patients with symptomatic nosocomial Clostridium difficile infections (CDI) are linked to other in-patients. However, this evidence was limited to one geographic area. We aimed to investigate the level of symptomatic CDI transmission in hospitals located across England from 2008 to 2012. METHODS: A generalized additive mixed-effects Poisson model was fitted to English hospital-surveillance data. After adjusting for seasonal fluctuations and between-hospital variation in reported CDI over time, possible clustering (transmission between symptomatic in-patients) of CDI cases was identified. We hypothesised that a temporal proximity would be reflected in the degree of correlation between in-hospital CDI cases per week. This correlation was modelled through a latent autoregressive structure of order 1 (AR(1)). FINDINGS: Forty-six hospitals (33 general, seven specialist, and six teaching hospitals) located in all English regions met our criteria. In total, 12,717 CDI cases were identified; seventy-five per cent of these occurred >48 hours after admission. There were slight increases in reports during winter months. We found a low, but statistically significant, correlation between successive weekly CDI case incidences (phi = 0.029, 95%CI: 0.009-0.049). This correlation was five times stronger in a subgroup analysis restricted to teaching hospitals (phi = 0.104, 95%CI: 0.048-0.159). CONCLUSIONS: The results suggest that symptomatic patient-to-patient transmission has been a source of CDI-acquisition in English hospitals in recent years, and that this might be a more important transmission route in teaching hospitals. Nonetheless, the weak correlation indicates that, in line with recent evidence, symptomatic cases might not be the primary source of nosocomial CDI in England
Density matrix operatorial solution of the non--Markovian Master Equation for Quantum Brownian Motion
An original method to exactly solve the non-Markovian Master Equation
describing the interaction of a single harmonic oscillator with a quantum
environment in the weak coupling limit is reported. By using a superoperatorial
approach we succeed in deriving the operatorial solution for the density matrix
of the system. Our method is independent of the physical properties of the
environment. We show the usefulness of our solution deriving explicit
expressions for the dissipative time evolution of some observables of physical
interest for the system, such as, for example, its mean energy.Comment: 16 pages, 1 figur
A perturbative approach to non-Markovian stochastic Schr\"odinger equations
In this paper we present a perturbative procedure that allows one to
numerically solve diffusive non-Markovian Stochastic Schr\"odinger equations,
for a wide range of memory functions. To illustrate this procedure numerical
results are presented for a classically driven two level atom immersed in a
environment with a simple memory function. It is observed that as the order of
the perturbation is increased the numerical results for the ensembled average
state approach the exact reduced state found via
Imamo\=glu's enlarged system method [Phys. Rev. A. 50, 3650 (1994)].Comment: 17 pages, 4 figure
- …