Quantum dynamics of the avian compass

The ability of migratory birds to orient relative to the Earth's magnetic field is believed to involve a coherent superposition of two spin states of a radical electron pair. However, the mechanism by which this coherence can be maintained in the face of strong interactions with the cellular environment has remained unclear. This Letter addresses the problem of decoherence between two electron spins due to hyperfine interaction with a bath of spin 1/2 nuclei. Dynamics of the radical pair density matrix are derived and shown to yield a simple mechanism for sensing magnetic field orientation. Rates of dephasing and decoherence are calculated ab initio and found to yield millisecond coherence times, consistent with behavioral experiments

The 2010 MW 6.8 Yushu (Qinghai, China) earthquake: constraints provided by InSAR and body wave seismology

By combining observations from satellite radar, body wave seismology and optical imagery, we have determined the fault segmentation and sequence of ruptures for the 2010 Mw 6.8 Yushu (China) earthquake. We have mapped the fault trace using displacements from SAR image matching, interferometric phase and coherence, and 2.5 m SPOT-5 satellite images. Modeling the event as an elastic dislocation with three segments fitted to the fault trace suggests that the southeast and northwest segments are near vertical, with the central segment dipping 70° to the southwest; slip occurs mainly in the upper 10 km, with a maximum slip of 1.5 m at a depth of 4 km on the southeastern segment. The maximum slip in the top 1 km (i.e., near surface) is up to 1.2 m, and inferred locations of significant surface rupture are consistent with displacements from SAR image matching and field observations. The radar interferograms show rupture over a distance of almost 80 km, much larger than initial seismological and field estimates of the length of the fault. Part of this difference can be attributed to slip on the northwestern segment of the fault being due to an Mw 6.1 aftershock two hours after the main event. The remaining difference can be explained by a non-uniform slip distribution with much of the moment release occurring at depths of less than 10 km. The rupture on the central and southeastern segments of the fault in the main shock propagated at a speed of 2.5 km/s southeastward toward the town of Yushu located at the end of this segment, accounting for the considerable building damage. Strain accumulation since the last earthquake on the fault segment beyond Yushu is equivalent to an Mw 6.5 earthquake

Understanding FEV1 for the purpose of cystic fibrosis registry comparisons: Does bias in annual review FEV1 affect between-centre comparison within the UK? An analysis of registry data

Rationale, aims and objective: We previously demonstrated that annual review %FEV1 under-estimates lung health of adults with CF compared to %FEV1 captured during periods of clinical stability. This has implications in the comparisons against registries with encounter-based FEV1, such as the US. It is uncertain whether this bias affects between-centre comparison within the UK. Previous funnel plot analyses have identified variation in annual review %FEV1 according to centre size, hence we investigated whether paired differences between annual review and best %FEV1 also vary according to centre size. Methods: This registry analysis included 18 adult CF centres in the UK with ≥80% completeness for best FEV1 data in 2014. Mean discrepancy between annual review and best %FEV1 is a surrogate for the extent by which annual review %FEV1 underestimates lung health; and was plotted against centre size. A Local Polynomial Regression (LOESS) curve was used to explore the relationship between the two variables. An appropriate model is fitted based on the LOESS curve to determine the strength of relationship between discrepancies in %FEV1 and centre size. Results: There is an inverted U-shaped relationship between mean discrepancies in %FEV1 and centre size. A regression of the paired mean difference in %FEV1 against centre size showed a significant improvement in the goodness of fit for a quadratic model (R2 = 23.8% for a quadratic model compared with 0.4% for a linear one; p = 0.048 for the quadratic term). Conclusions: Annual review %FEV1 under-estimated lung health of adults from small and large centres in the UK to a greater extent compared to medium-sized centres. A plot of %FEV1 against centre size (e.g. funnel plot comparison) would be affected by systematic bias in annual review %FEV1. Therefore, annual review %FEV1 is an unreliable metric to compare health outcomes of adult CF centres within the UK

Rescue therapy within the UK Cystic Fibrosis registry: an exploration of the predictors of intravenous antibiotic use amongst adults with CF

Background and objective: Intravenous (i.v.) antibiotics are needed for rescue when preventative therapy fails to achieve stability among adults with cystic fibrosis (CF). Understanding the distribution of i.v. days can provide insight into the care that adults with CF need. We aim to determine the baseline characteristics that are associated with higher i.v. use, in particular to test the hypothesis that prior-year i.v. use is associated with future-year i.v. use. Methods: This is a cross-sectional analysis of the 2013–2014 UK CF registry data. Stepwise logistic regression was performed using current-year i.v. days as the dependent variable, and demographic variables including prior-year i.v. days as the covariates. Based on these results, study sample was divided into clinically meaningful subgroups using analysis similar to tree-based method. Results: Data were available for 4269 adults in 2013 and 4644 adults in 2014. Prior-year i.v. use was the strongest predictor for current-year i.v. use followed by forced expiratory volume in 1 s (FEV1). Adults with high prioryear i.v. use (>14 days) continued to require high levels of i.v., regardless of FEV1. Those with high prior-year i. v. use and FEV1 ≥70% had higher current-year i.v. days compared to adults with low prior-year i.v. use and FEV1 <40% (28 days, interquartile range (IQR): 11–41 days vs 14 days, IQR: 0–28 days; Mann–Whitney P-value <0.001 in 2013). Conclusion: CF people with prior high levels of rescue often continue to need high levels of rescue even if they have good FEV1. The reasons for this require further investigations

Documentation of Ancestral Caddo Ceramic Vessels in the Smith County Historical Museum Collections

This report puts on record the collection of 34 ancestral Caddo vessels held by the Smith County Historical Museum (SCHM) in Tyler, Texas. Most of the collection was donated to the SCHM in 2013, but several were also donated in 1985 (Carol Kehl, April 2014 personal communication). The vessels in this collection have been documented following the methods employed by the Friends of Northeast Texas Archaeology and Archeological & Environmental Consultants, LLC on a number of ancestral Caddo ceramic collections from East Texas archaeological sites (e.g., Perttula 2011, 2013, 2014; Perttula and Nelson 2013; Perttula and Thacker 2014; Perttula et al. 2007, 2009a, 2009b, 2010a, 2010b, 2010c, 2012a, 2012b, 2012c, 2013, 2014). The provenance of the Caddo vessels includes a number of vessels from sites at Lake O’ the Pines in the Big Cypress Creek basin, while the other 10 vessels are believed to have been collected from sites in the upper Neches River basin in Smith County, Texas. We discuss these conclusions in the “Summary and Conclusions” section of the report, relying on the decorative styles and types of the vessels (see Suhm and Jelks 1962) to sort them into the material culture remains known to be associated with different ancestral Caddo cultural groups in East Texas

Predicting dementia risk in primary care: development and validation of the Dementia Risk Score using routinely collected data

BACKGROUND: Existing dementia risk scores require collection of additional data from patients, limiting their use in practice. Routinely collected healthcare data have the potential to assess dementia risk without the need to collect further information. Our objective was to develop and validate a 5-year dementia risk score derived from primary healthcare data. METHODS: We used data from general practices in The Health Improvement Network (THIN) database from across the UK, randomly selecting 377 practices for a development cohort and identifying 930,395 patients aged 60-95 years without a recording of dementia, cognitive impairment or memory symptoms at baseline. We developed risk algorithm models for two age groups (60-79 and 80-95 years). An external validation was conducted by validating the model on a separate cohort of 264,224 patients from 95 randomly chosen THIN practices that did not contribute to the development cohort. Our main outcome was 5-year risk of first recorded dementia diagnosis. Potential predictors included sociodemographic, cardiovascular, lifestyle and mental health variables. RESULTS: Dementia incidence was 1.88 (95 % CI, 1.83-1.93) and 16.53 (95 % CI, 16.15-16.92) per 1000 PYAR for those aged 60-79 (n = 6017) and 80-95 years (n = 7104), respectively. Predictors for those aged 60-79 included age, sex, social deprivation, smoking, BMI, heavy alcohol use, anti-hypertensive drugs, diabetes, stroke/TIA, atrial fibrillation, aspirin, depression. The discrimination and calibration of the risk algorithm were good for the 60-79 years model; D statistic 2.03 (95 % CI, 1.95-2.11), C index 0.84 (95 % CI, 0.81-0.87), and calibration slope 0.98 (95 % CI, 0.93-1.02). The algorithm had a high negative predictive value, but lower positive predictive value at most risk thresholds. Discrimination and calibration were poor for the 80-95 years model. CONCLUSIONS: Routinely collected data predicts 5-year risk of recorded diagnosis of dementia for those aged 60-79, but not those aged 80+. This algorithm can identify higher risk populations for dementia in primary care. The risk score has a high negative predictive value and may be most helpful in 'ruling out' those at very low risk from further testing or intensive preventative activities

Comparing the reliability of networks by spectral analysis

We provide a method for the ranking of the reliability of two networks with the same connectance. Our method is based on the Cheeger constant linking the topological property of a network with its spectrum. We first analyze a set of twisted rings with the same connectance and degree distribution, and obtain the ranking of their reliability using their eigenvalue gaps. The results are generalized to general networks using the method of rewiring. The success of our ranking method is verified numerically for the IEEE57, the Erd\H{o}s-R\'enyi, and the Small-World networks.Comment: 7 pages, 3 figure

The magnetic properties of 177^{\rm 177}Hf and 180^{\rm 180}Hf in the strong coupling deformed model

This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2$^-$, 51.4 m, 2740 keV state in $^{\rm 177}$Hf and the 8$^-$, 5.5 h, 1142 keV state in $^{\rm 180}$Hf by the method of on-line nuclear orientation. Also included are results on the angular distributions of gamma transitions in the decay of the $^{\rm 177}$Hf isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2$^+$, 1.1 s, isomer at 1315 keV and on the 9/2$^+$, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the g$_{\rm R}$ parameter upon the quasi-proton and quasi-neutron make up of high-K isomeric states in this region.Comment: 9 pages, 9 figures, accepted for publication in Physical Review