Neural processing of imminent collision in humans

Detecting a looming object and its imminent collision is imperative to survival. For most humans, it is a fundamental aspect of daily activities such as driving, road crossing and participating in sport, yet little is known about how the brain both detects and responds to such stimuli. Here we use functional magnetic resonance imaging to assess neural response to looming stimuli in comparison with receding stimuli and motion-controlled static stimuli. We demonstrate for the first time that, in the human, the superior colliculus and the pulvinar nucleus of the thalamus respond to looming in addition to cortical regions associated with motor preparation. We also implicate the anterior insula in making timing computations for collision events

UK Renal Registry 18th Annual Report: Chapter 11 2014 Multisite Dialysis Access Audit in England, Northern Ireland and Wales and 2013 PD One Year Follow-up: National and Centre-specific Analyses

Data are presented from the third combined vascular and peritoneal dialysis access audit. In 2014, 53 centres in England, Wales and Northern Ireland (out of 62) returned data on first access from 4,339 incident haemodialysis (HD) patients and 1,090 incident peritoneal dialysis (PD) patients. Of the 5,429 incident patients, 20.1% started dialysis on PD, 27.8% started with an arteriovenous fistula (AVF), 1.0% with an arteriovenous graft (AVG), 27.1% on a tunnelled line (TL) and 24.0% on a non-tunnelled line (NTL). Older patients (565 years) were more likely to start haemodialysis using AVF compared to their younger counterparts (36.2% vs. 32.8%). Thirteen of the nineteen centres (68%) using the physician led percutaneous insertion technique had over 20% of their incident patients starting on PD when compared to only seven out of fourteen centres (50%) which used single technique (open surgical or laparoscopic) for their PD catheter insertion. Wide variations were apparent between centres for use of AVF as the first haemodialysis access ranging from 10-54%. Eight of the 49 centres were achieving close to the 65% target for AV fistula in their incident patients. Length of time known to nephrology services and likelihood of commencing dialysis using either an AVF or a PD catheter are strongly associated. Patients who were known to a nephrologist for over one year were more likely to start dialysis with AVF, as compared to those who were referred between 90-365 days (39.2% vs. 24.6%). Similarly, patients who were known to a nephrologist between 90 days and one year were more likely to start on PD when compared to patients who were referred ,90 days prior to dialysis start (26.9% vs. 9.1%). By comparison, amongst the late presenters, only 3.5% had first access documented as an AVF and 87.3% started dialysis on either a tunnelled line or a nontunnelled line. Initial surgical assessment was a key determinant of the likelihood of AVF formation. Of the incident patients known to renal services for longer than three months and in those assessed by a surgeon at least three months prior to starting dialysis, 71.4% started dialysis with an AVF whereas of those who were not seen by a surgeon only 10.8% did. Thirty one of the 38 centres were 2 or 3 standard deviations below the 85% target for prevalent haemodialysis patients with an AV fistula. For centres returning data on one-year peritoneal dialysis outcomes, the majority of centres (28/32) maintained 550% of patients on PD at one year, having censored for transplantation. This report demonstrates wide variations in practice between centres across several domains in the provision of dialysis access and further work will be required to understand the underlying reasons

When is Quantum Decoherence Dynamics Classical?

A direct classical analog of quantum decoherence is introduced. Similarities and differences between decoherence dynamics examined quantum mechanically and classically are exposed via a second-order perturbative treatment and via a strong decoherence theory, showing a strong dependence on the nature of the system-environment coupling. For example, for the traditionally assumed linear coupling, the classical and quantum results are shown to be in exact agreement.Comment: 5 pages, no figures, to appear in Physical Review Letter

Suppression of decoherence via strong intra-environmental coupling

We examine the effects of intra-environmental coupling on decoherence by constructing a low temperature spin--spin-bath model of an atomic impurity in a Debye crystal. The impurity interacts with phonons of the crystal through anti-ferromagnetic spin-spin interactions. The reduced density matrix of the central spin representing the impurity is calculated by dynamically integrating the full Schroedinger equation for the spin--spin-bath model for different thermally weighted eigenstates of the spin-bath. Exact numerical results show that increasing the intra-environmental coupling results in suppression of decoherence. This effect could play an important role in the construction of solid state quantum devices such as quantum computers.Comment: 4 pages, 3 figures, Revtex fil

“some kind of thing it aint us but yet its in us”: David Mitchell, Russell Hoban, and metafiction after the millennium

This article appraises the debt that David Mitchell’s Cloud Atlas owes to the novels of Russell Hoban, including, but not limited to, Riddley Walker. After clearly mapping a history of Hoban’s philosophical perspectives and Mitchell’s inter-textual genre-impersonation practice, the article assesses the degree to which Mitchell’s metatextual methods indicate a nostalgia for by-gone radical aesthetics rather than reaching for new modes of its own. The article not only proposes several new backdrops against which Mitchell’s novel can be read but also conducts the first in-depth appraisal of Mitchell’s formal linguistic replication of Riddley Walker

Manifold algorithmic errors in quantum computers with static internal imperfections

The inevitable existence of static internal imperfections and residual interactions in some quantum computer architectures result in internal decoherence, dissipation, and destructive unitary shifts of active algorithms. By exact numerical simulations we determine the relative importance and origin of these errors for a Josephson charge qubit quantum computer. In particular we determine that the dynamics of a CNOT gate interacting with its idle neighboring qubits via native residual coupling behaves much like a perturbed kicked top in the exponential decay regime, where fidelity decay is only weakly dependent on perturbation strength. This means that retroactive removal of gate errors (whether unitary or non-unitary) may not be possible, and that effective error correction schemes must operate concurrently with the implementation of subcomponents of the gate

Widespread pain and depression are key modifiable risk factors associated with reduced social participation in older adults: A prospective cohort study in primary care.

In older adults, reduced social participation increases the risk of poor health-related quality of life, increased levels of inflammatory markers and cardiovascular disease, and increased mortality. Older adults frequently present to primary care, which offers the potential to deliver interventions at the point of care to increase social participation. The aim of this prospective study was to identify the key modifiable exposures that were associated with reduced social participation in a primary care population of older adults.The study was a population-based prospective cohort study. Participants (n = 1991) were those aged ≥65 years who had completed questionnaires at baseline, and 3 and 6-year follow-ups. Generalized linear mixed modeling framework was used to test for associations between exposures and decreasing social participation over 6 years.At baseline, 44% of participants reported reduced social participation, increasing to 49% and 55% at 3 and 6-year follow-up. Widespread pain and depression had the strongest independent association with reduced social participation over the 6-year follow-up period. The prevalence of reduced social participation for those with widespread pain was 106% (adjusted incidence rate ratio 2.06, 95% confidence interval 1.72, 2.46), higher than for those with no pain. Those with depression had an increased prevalence of 82% (adjusted incidence rate ratio 1.82, 95% confidence interval 1.62, 2.06). These associations persisted in multivariate analysis.Population ageing will be accompanied by increasing numbers of older adults with pain and depression. Future trials should assess whether screening for widespread pain and depression, and targeting appropriate treatment in primary care, increase social participation in older people