A Mechanism for Ventricular Expansion in Communicating Hydrocephalus

This report investigates a new possible molecular mechanism for the pathogenesis of hydrocephalus. New research by Dr. Miles Johnston has found that the injection of anti beta_1 integrin antibodies into the ventricle of rats causes a drop in parenchymal pressure and causes the cerebral ventricles to enlarge which is characteristic of hydrocephalus. We investigate intramantle pressure gradients as a possible force to enlarge the ventricles and we propose a new poroelastic model incorporating the effect of the antibodies to determine if they are a possible mechanism for hydrocephalus

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

“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

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

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

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

Assessing physical symptoms during the postpartum period: reliability and validity of the primary health questionnaire somatic symptom subscale (PHQ-15)

© 2017 Informa UK Limited, trading as Taylor & Francis GroupIntroduction: This study aimed at establishing the reliability and validity of the primary health questionnaire (PHQ-15) somatic symptom severity subscale for postpartum women. Methods: Women (N = 495) completed the PHQ-15 approximately 6 weeks postpartum during the baseline phase of a randomized controlled trial evaluating a writing intervention for postnatal health in England. Reliability was assessed using internal consistency statistics and convergent validity by comparing differences in self-reported physical health, health-related quality of life (QoL) and primary care usage by PHQ-15 symptom severity category. Results: Cronbach’s α for the PHQ-15 was 0.73 and item-total statistics met recommended guidelines. Validity analyzes showed 6% of women reported severe symptoms, 17% medium, 50% low and 27% minimal symptoms. Women with severe symptoms reported poorer overall physical health, poorer physical health-related QoL and greater use of primary care. Women with severe symptoms also rated their baby’s health as worse and used primary care more for their baby. Discussion: This study suggests the PHQ-15 has the potential to be a useful and valid measure of physical symptoms in postpartum women in high-income countries

Exponential Divergence and Long Time Relaxation in Chaotic Quantum Dynamics

Phase space representations of the dynamics of the quantal and classical cat map are used to explore quantum--classical correspondence in a K-system: as $\hbar \to 0$, the classical chaotic behavior is shown to emerge smoothly and exactly. The quantum dynamics near the classical limit displays both exponential separation of adjacent distributions and long time relaxation, two characteristic features of classical chaotic motion.Comment: 10 pages, ReVTeX, to appear in Phys. Rev. Lett. 13 figures NOT included. Available either as LARGE (uuencoded gzipped) postscript files or hard-copies from [email protected]