Spatial mapping of hepatitis C prevalence in recent injecting drug users in contact with services.

In developed countries the majority of hepatitis C virus (HCV) infections occur in injecting drug users (IDUs) with prevalence in IDUs often high, but with wide geographical differences within countries. Estimates of local prevalence are needed for planning services for IDUs, but it is not practical to conduct HCV seroprevalence surveys in all areas. In this study survey data from IDUs attending specialist services were collected in 52/149 sites in England between 2006 and 2008. Spatially correlated random-effects models were used to estimate HCV prevalence for all sites, using auxiliary data to aid prediction. Estimates ranged from 14% to 82%, with larger cities, London and the North West having the highest HCV prevalence. The methods used generated robust estimates for each area, with a well-identified spatial pattern that improved predictions. Such models may be of use in other areas of study where surveillance data are sparse

Stabilizing an atom laser using spatially selective pumping and feedback

We perform a comprehensive study of stability of a pumped atom laser in the presence of pumping, damping and outcoupling. We also introduce a realistic feedback scheme to improve stability by extracting energy from the condensate and determine its effectiveness. We find that while the feedback scheme is highly efficient in reducing condensate fluctuations, it usually does not alter the stability class of a particular set of pumping, damping and outcoupling parameters.Comment: 7 figure

Paired atom laser beams created via four-wave mixing

A method to create paired atom laser beams from a metastable helium atom laser via four-wave mixing is demonstrated. Radio frequency outcoupling is used to extract atoms from a Bose Einstein condensate near the center of the condensate and initiate scattering between trapped and untrapped atoms. The unequal strengths of the interactions for different internal states allows an energy-momentum resonance which leads to the creation of pairs of atoms scattered from the zero-velocity condensate. The resulting scattered beams are well separated from the main atom laser in the 2-dimensional transverse atom laser profile. Numerical simulations of the system are in good agreement with the observed atom laser spatial profiles, and indicate that the scattered beams are generated by a four-wave mixing process, suggesting that the beams are correlated.Comment: 5 pages, 3 figure

Experimental measurement and calculation of losses in planar radial magnetic bearings

The loss mechanisms associated with magnetic bearings have yet to be adequately characterized or modeled analytically and thus pose a problem for the designer of magnetic bearings. This problem is particularly important for aerospace applications where low power consumption of components is critical. Also, losses are expected to be large for high speed operation. The iron losses in magnetic bearings can be divided into eddy current losses and hysteresis losses. While theoretical models for these losses exist for transformer and electric motor applications, they have not been verified for magnetic bearings. This paper presents the results from a low speed experimental test rig and compares them to calculated values from existing theory. Experimental data was taken over a range of 90 to 2,800 rpm for several bias currents and two different pole configurations. With certain assumptions agreement between measured and calculated power losses was within 16 percent for a number of test configurations

A meta‐analytic review of the Self‐Administered Interview©: Quantity and accuracy of details reported on initial and subsequent retrieval attempts

The Self-Administered Interview (SAI©) is designed to elicit detailed witness reports in the aftermath of incidents. In two sets of meta-analyses, we compared the number of correct details reported, the number of incorrect details reported, and the accuracy of reports provided by witnesses in initial reports (SAI© vs. other reporting formats) and in subsequent accounts (initial SAI© vs. no initial SAI©). The number of comparisons ranged from 15 to 19, (N= 722 to 977). For initial accounts, the SAI© was associated with more correct details and more incorrect details than other reporting formats; accuracy was slightly lower for the SAI© than for other reporting formats. Subsequent accounts were more detailed and accurate for witnesses who had completed an initial SAI© than for those who had not. The SAI© is an effective tool for capturing detailed initial accounts and for preserving witness memory until a formal interview can be conducted

Distinct fos-expressing neuronal ensembles in the ventromedial prefrontal cortex mediate food reward and extinction memories

In operant learning, initial reward-associated memories are thought to be distinct from subsequent extinction-associated memories. Memories formed during operant learning are thought to be stored in “neuronal ensembles.” Thus, we hypothesize that different neuronal ensembles encode reward- and extinction-associated memories. Here, we examined prefrontal cortex neuronal ensembles involved in the recall of reward and extinction memories of food self-administration.Wefirst trained rats to lever press for palatable food pellets for 7 d (1 h/d) and then exposed them to 0, 2, or 7 daily extinction sessions in which lever presses were not reinforced. Twenty-four hours after the last training or extinction session, we exposed the rats to either a short 15 min extinction test session or left them in their homecage (a control condition). We found maximal Fos (a neuronal activity marker) immunoreactivity in the ventral medial prefrontal cortex of rats that previously received 2 extinction sessions, suggesting that neuronal ensembles in this area encode extinction memories. We then used the Daun02 inactivation procedure to selectively disrupt ventral medial prefrontal cortex neuronal ensembles that were activated during the 15 min extinction session following 0 (no extinction) or 2 prior extinction sessions to determine the effects of inactivating the putative food reward and extinction ensembles, respectively, on subsequent nonreinforced food seeking 2 d later. Inactivation of the food reward ensembles decreased food seeking, whereas inactivation of the extinction ensembles increased food seeking. Our results indicate that distinct neuronal ensembles encoding operant reward and extinction memories intermingle within the same cortical area

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

Low levels of hepatitis C diagnosis and testing uptake among people who inject image and performance enhancing drugs in England and Wales, 2012-15

People injecting image and performance enhancing drugs (IPEDs) have traditionally not been perceived as being at high risk of hepatitis C virus (HCV) infection. However, recent studies indicate the HCV antibody (anti-HCV) prevalence in this group is 10-times that in the general population. HCV testing uptake and undiagnosed infections are examined using data from a voluntary unlinked-anonymous survey. Method People injecting IPEDs across England and Wales completed a short bio-behavioural survey (2012–15). Anti-HCV status and self-reports of HCV testing were used in the analysis. Results The participants median age was 31 years, 98% were men, 14% had also injected psychoactive drugs and the anti-HCV prevalence was 4.8% (N = 564). Among those who had never injected psychoactive drugs the anti-HCV prevalence was 1.4%; among those who had recently injected psychoactive drugs (preceding 12 months) prevalence was 39% and among those who had done this previously 14% (p < 0.001). Overall, 37% had been tested for HCV: among those who had recently injected psychoactive drugs 78% had been tested, as had 56% of those who had injected psychoactive drugs previously; 33% of those never injecting psychoactive drugs were tested (p < 0.001). Overall, 44% of those with anti-HCV were aware of this; however, only 14% of those who had never injected psychoactive drugs were aware. Conclusions One-in-twenty people who inject IPEDs have anti-HCV. HCV infections among those who had never injected psychoactive drugs were mostly undiagnosed, though this group had a lower prevalence. Targeted HCV testing interventions are also needed for those injecting IPEDs