Updated analysis of the dynamical relation between asteroid 2003 EH1 and comets C/1490 Y1 and C/1385 U1

The asteroid 2003 EH1, proposed as the parent body of the Quadrantid meteor shower, is thought to be the remnant of a past cometary object, tentatively identified with the historical comets C/1490 Y1 and C/1385 U1. In the present work we use recovery astrometry to extend the observed arc of 2003 EH1 from 10 months to about 5 years, enough to exclude the proposed direct relationship of the asteroid with both of the comets.Comment: Submitted to Monthly Notices of the RAS Letters Updated with a new table and other minor change

GPS Velocity and Strain Rate Fields in Southwest Anatolia from Repeated GPS Measurements

Southwestern Turkey is a tectonically active area. To determine kinematics and strain distribution in this region, a GPS network of sixteen stations was established. We have used GPS velocity field data for southwest Anatolia from continuous measurements covering the period 2003 to 2006 to estimate current crustal deformation of this tectonically active region. GPS data were processed using GAMIT/GLOBK software and velocity and strain rate fields were estimated in the study area. The measurements showed velocities of 15–30 mm/yr toward the southwest and strain values up to 0.28–8.23×10−8. Results showed that extension has been determined in the Burdur-Isparta region. In this study, all of strain data reveal an extensional neotectonic regime through the northeast edge of the Isparta Angle despite the previously reported compressional neotectonic regime. Meanwhile, results showed some small differences relatively with the 2006 model of Reilinger et al. As a result, active tectonic movements, in agreement with earthquake fault plane solutions showed important activity

Crustal strain partitioning and the associated earthquake hazard in the eastern Sunda-Banda Arc

We use Global Positioning System (GPS) measurements of surface deformation to show that the convergence between the Australian Plate and Sunda Block in eastern Indonesia is partitioned between the megathrust and a continuous zone of back-arc thrusting extending 2000 km from east Java to north of Timor. Although deformation in this back-arc region has been reported previously, its extent and the mechanism of convergence partitioning have hitherto been conjectural. GPS observations establish that partitioning occurs via a combination of anticlockwise rotation of an arc segment called the Sumba Block, and left-lateral movement along a major NE-SW strike-slip fault west of Timor. We also identify a westward extension of the back-arc thrust for 300 km onshore into East Java, accommodating slip of ∼6 mm/yr. These results highlight a major new seismic threat for East Java and draw attention to the pronounced seismic and tsunami threat to Bali, Lombok, Nusa Tenggara, and other coasts along the Flores Sea

Estimates of Seismic Potential in the Marmara Sea Region from Block Models of Secular Deformation Constrained by Global Positioning System Measurements

We model the geodetically observed secular velocity field in northwestern Turkey with a block model that accounts for recoverable elastic-strain accumulation. The block model allows us to estimate internally consistent fault slip rates and locking depths. The northern strand of the North Anatolian fault zone (NAFZ) carries approximately four times as much right-lateral motion (∼24 mm/yr) as does the southern strand. In the Marmara Sea region, the data show strain accumulation to be highly localized. We find that a straight fault geometry with a shallow locking depth of 6-7 km fits the observed Global Positioning System velocities better than does a stepped fault geometry that follows the northern and eastern edges of the sea. This shallow locking depth suggests that the moment release associated with an earthquake on these faults should be smaller, by a factor of 2.3, than previously inferred assuming a locking depth of 15 km.Earth and Planetary Science

Present Day Kinematics of the Eastern California Shear Zone from a Geodetically Constrained Block Model

We use Global Positioning System (GPS) data from 1993–2000 to determine horizontal velocities of 65 stations in eastern California and western Nevada between 35° and 37° N. We relate the geodetic velocities to fault slip rates using a block model that enforces path integral constraints over geologic and geodetic time scales and that includes the effects of elastic strain accumulation on faults locked to a depth of 15 km. The velocity of the Sierra Nevada block with respect to Nevada is 11.1±0.3 mm/yr, with slip partitioned across the Death Valley, (2.8±0.5 mm/yr), Panamint Valley (2.5±0.8 mm/yr), and Airport Lake/Owens Valley (5.3±0.7/4.6±0.5 mm/yr) faults. The western Mojave block rotates at 2.1±0.8°/My clockwise, with 3.7±0.7 mm/yr of left lateral motion across the western Garlock Fault. We infer 11±2 mm/yr of right lateral motion across the Mojave region of the Eastern California Shear Zone

Characterization of resident surgeon participation during carotid endarterectomy and impact on perioperative outcomes

IntroductionThe impact of resident surgeon participation during vascular procedures on postoperative outcomes is incompletely understood. We characterized resident physician participation during carotid endarterectomy (CEA) procedures within the 2005-2009 American College of Surgeons National Surgical Quality Improvement Participant Use Datafile and evaluated associations with procedural characteristics and perioperative adverse events.MethodsCEAs were identified using primary current procedural terminology codes; those performed simultaneously with other major procedures or unknown resident participation status were excluded. Group-wise comparisons based on resident participation status were performed using χ2 or Fisher's exact test for categorical variables and t tests or nonparametric methods for continuous variables. Associations with perioperative adverse events (major = stroke, death, myocardial infarction, or cardiac arrest; minor = peripheral nerve injury, bleeding requiring transfusion, surgical site infection, or wound disruption) were assessed using multivariable logistic regression models adjusting for other known risk factors.ResultsA total of 25,280 CEA procedures were analyzed, of which residents participated in 13,705 (54.2%), while residents were absent in 11,575 (45.8%). Among CEAs with resident physician participation, resident level was categorized as junior (postgraduate year [PGY] 1-2) in 21.9%, senior (PGY 3-5) in 52.7%, and fellow (PGY ≥6) in 25.3%. Major adverse event rates with and without resident participation were 1.9% versus 2.1%, and minor adverse event rates with and without resident participation were 0.9% versus 1.0%, respectively. In multivariable models, resident physician participation was not associated with perioperative risk for major adverse events (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.75-1.08) or minor adverse events (OR, 0.93; 95% CI, 0.72-1.21).ConclusionsResident surgeon participation during CEA is not associated with risk of adverse perioperative events

Identifying Trends in Masterplanning: A Typological Classification System

This document is the Accepted Manuscript version of the following article: Robert Adam, and Claire Jamieson, ‘Identifying trends in masterplanning: A typological classification system’, URBAN DESIGN International, Vol. 19 (4): 274-290, December 2014. The final publication is available at Springer via https://doi.org/10.1057/udi.2013.24.This article reports research carried out to develop a new typological method for the analysis of masterplans. This quantitative method of analysis can be used to produce comparative data that will help in the comparison of urban design typologies and their development over time. This article sets out the research to date, describing how the initial aims have developed from simple analysis to the creation of an analytical tool with wide applications. Comprising a detailed taxonomy of urban design features gathered from a wide database of recent and emerging masterplans, the system provides opportunities for further study such as trends, qualitative comparison against quantitative measurement, and comparison of aims and outcomes. This article will describe the methodology and process of research, while elaborating on the potential of the tool.Peer reviewedFinal Accepted Versio

First recorded eruption of Nabro volcano, Eritrea, 2011

We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of re- gional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodi- gious quantity of SO2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic signifi- cance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of Editorial responsibility: G. Giordano the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shal- low, NW–SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response miti- gated the human costs of the eruption