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

Documentation of Caddo Vessels in the Robert L. Turner Collection at Stephen F. Austin State University

Perttula et al. (2010) documented more than 300 ceramic vessels in the Robert L. Turner, Jr. collection from ancestral Caddo burial sites in East Texas, primarily from the Big Cypress Creek basin, but also including vessels from sites in the middle Sabine, lower Sulphur River, and Neches/Angelina River basins. When the Turner collection was donated to Stephen F. Austin State University (SFASU) in 2012, it was noted that some of the vessels in the collection had not been documented by Perttula et al. (2010). In the spring of 2014 we had an opportunity to remedy the situation, and with the permission of DR. George Avery of the Anthropology and Archaeology Laboratory at SFASU, we have documented an additional 38 vessels in the Turner collection. These vessels are from the G. W. Rumsey (41CP3), Tuck Carpenter (41CP5), Harold Williams (41CP10), B. J. Horton (41CP20), and Alex Justiss (41TT13) sites in the Big Cypress Creek basin (Figure 1)

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 Caddo Vessels and Sherds in the Herrington Collection at Tyler Junior College, in Smith County, Texas

This report puts on record the collection of ancestral Caddo vessels and sherds held by Tyler Junior College (TJC) in Tyler, Texas. This collection was donated by Al Herrington to TJC in 2012. The vessels and sherds 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 and sherd assemblage is not known with certainty, but (as we discuss in the Summary and Conclusions section of the report) the decorative styles of the vessels and sherds indicate they are from East Texas Caddo sites, most likely from sites in the Neches and Sabine river basins

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

The Sanders Site (41LR2): A Middle to Historic Caddo Settlement and Mound Center on the Red River in Lamar County, Texas

The T. M. Sanders site (41LR2) is one of the more important (although still not well known or intensively studied) ancestral Caddo sites known in East Texas, primarily because of its two earthen mounds and the well-preserved mortuary features of Caddo elite persons buried in Mound No. 1 (the East Mound). Archaeological work began at the site in 1931 by The University of Texas at Austin, with sporadic work by members of the Dallas Archeological Society in the 1940s and 1950s. Archaeological and bioarchaeological interpretations of the findings from this work at the Sanders site began with Krieger’s analyses of the burial features and associated funerary objects (including marine shell gorgets, shell beads, arrow points, and ceramic vessels). These analyses and studies continue to the present day, and rely upon the reanalysis and reinterpretation of the archaeological and bioarchaeological materials recovered in the Pearce and Jackson and Jackson\u27s work. Although the Sanders site is not dated by radiocarbon analyses, the general consensus is that the main Caddo occupation took place around ca. A.D. 1100-1300, contemporaneous with related sites downstream along the Red River near its confluence with the Kiamichi River, and other sites in the Sabine River basin. A late 17th-early 18th century Caddo occupation is also present at the Sanders site, but remains poorly known. Harris and Harris commented that European “trade material is exceptionally scarce” at the Sanders site, but they do note that 478 glass beads had been found at the site. Harris had previously stated that several Caddo burials with European trade goods had been found along Bois d’Arc Creek south of Mound No. 2, the larger or West Mound. According to Edward B. Jelks, an Historic Caddo area investigated by Lester Wilson (an avocational archaeologist from Wylie, Texas) was about 100 m south of the two mounds at the Sanders site. This may be one of the areas identified by Jackson between ca. 90-150 m south of the mounds where he noted concentrations of triangular arrow points, small end scrapers, flint awls, and other stone tools. A 1971 map in the TARL files drawn by Dee Ann Story locates the historic Caddo settlement east of Bois d’Arc Creek and south of Mound No. 2

Solving Tree Problems with Category Theory

Artificial Intelligence (AI) has long pursued models, theories, and techniques to imbue machines with human-like general intelligence. Yet even the currently predominant data-driven approaches in AI seem to be lacking humans' unique ability to solve wide ranges of problems. This situation begs the question of the existence of principles that underlie general problem-solving capabilities. We approach this question through the mathematical formulation of analogies across different problems and solutions. We focus in particular on problems that could be represented as tree-like structures. Most importantly, we adopt a category-theoretic approach in formalising tree problems as categories, and in proving the existence of equivalences across apparently unrelated problem domains. We prove the existence of a functor between the category of tree problems and the category of solutions. We also provide a weaker version of the functor by quantifying equivalences of problem categories using a metric on tree problems.Comment: 10 pages, 4 figures, International Conference on Artificial General Intelligence (AGI) 201