Synchronous N-S and E-W extension at the Tibet-to-Himalaya transition in NW Bhutan

Despite ~50 Myr of continuous continent-continent collision, contractional structures in the Himalayan-Tibetan orogen are today limited to the northern and southern margins of the system, while extension dominates much of the interior. On the Tibetan Plateau, Cenozoic E-W extension has been accommodated by strike-slip faults and extensional grabens, while N-S extension at the Tibet-to-Himalaya transition has been accommodated by the South Tibetan fault system (STFS). The genetic relationship between N-S and E-W extension is disputed, although age constraints indicate temporal overlap of at least 7 Myr. In NW Bhutan the two intersect where the STFS basal detachment is cut by the Yadong cross structure (YCS), an extensional half graben that provides a rare opportunity to constrain relative timings. We report U-Pb zircon dates from four STFS footwall leucogranites consistent with episodic magmatism during the middle-late Miocene and in situ U(-Th)-Pb monazite and xenotime dates from three metasedimentary rocks ranging from late Oligocene to middle Miocene. We suggest that amphibolite facies footwall metamorphism was ongoing at the time the basal STFS detachment initiated as a ductile structure in the middle-late Miocene. Late-stage granitic intrusions may reflect footwall melting during extensional exhumation along the STFS, but post-metamorphic and post-intrusion fabrics suggest that most displacement occurred after emplacement of the youngest granites. Some of the oldest YCS-related fabrics are found in a deformed 14 Ma leucogranite, implying middle Miocene ductile deformation. This observation, along with evidence for subsequent brittle YCS deformation, suggests that N-S and E-W extensional structures in the area had protracted and overlapping deformation histories

Localization of Quaternary slip rates in an active rift in 10(5) years: an example from central Greece constrained by U-234-Th-230 coral dates from uplifted paleoshorelines

Mapping, dating, and modeling of paleoshorelines uplifted in the footwall of the 1981 Gulf of Corinth earthquake fault, Greece (Ms 6.9–6.7), are used to assess its slip rate history relative to other normal faults in the area and study strain localization. The 234U-230Th coral ages from Cladocora caespitosa date uplifted shoreface sediments, and paleoshorelines from glacioeustatic sea level highstands at 76, (possibly) 100, 125, 175, 200, 216, 240, and 340 ka. Uplifted Quaternary and Holocene paleoshorelines decrease in elevation toward the western tip of the fault, exhibiting larger tilt angles with age, showing that uplift is due to progressive fault slip. Since 125 ka, uplift rates varied from 0.25 to 0.52 mm/yr over a distance of 5 km away from the fault tip. Tilting was also occurring prior to 125 ka, but uplift rates were lower because the 125 ka paleoshoreline is at 77% of the elevation of the 240 ka paleoshoreline despite being nearly half its age. Comparison of paleoshoreline elevations and sedimentology with the Quaternary sea level curve shows that slip rates increased by a factor of 3.2 ± 0.2 at 175 ± 75 ka, synchronous with cessation of activity on a neighboring normal fault at 382–112 ka. We suggest that the rapid localization of up to 10–15 mm/yr of extension into the narrow gulf (∼30 km wide) resulted from synchronous fault activity on neighboring faults followed by localization rather than sequential faulting, with consequences for the mechanism controlling localization of extension

Transmission properties of a single metallic slit: From the subwavelength regime to the geometrical-optics limit

In this work we explore the transmission properties of a single slit in a metallic screen. We analyze the dependence of these properties on both slit width and angle of incident radiation. We study in detail the crossover between the subwavelength regime and the geometrical-optics limit. In the subwavelength regime, resonant transmission linked to the excitation of waveguide resonances is analyzed. Linewidth of these resonances and their associated electric field intensities are controlled by just the width of the slit. More complex transmission spectra appear when the wavelength of light is comparable to the slit width. Rapid oscillations associated to the emergence of different propagating modes inside the slit are the main features appearing in this regime.Comment: Accepted for publication in Phys. Rev.

First trimester screening of serum soluble fms-like tyrosine kinase-1 and placental growth factor predicting hypertensive disorders of pregnancy

AbstractObjectiveTo assess the accuracy of first trimester soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) in predicting pregnancy hypertension and pre-eclampsia; and compare with the accuracy of routinely collected maternal and clinical risk factors.Study designIn this population-based cohort study, serum sFlt-1 and PlGF levels were measured in first trimester in 2,681 women with singleton pregnancies in New South Wales, Australia.Main outcome measuresPrediction of pregnancy hypertension and pre-eclampsia.ResultsThere were 213 (7.9%) women with pregnancy hypertension, including 68 (2.5%) with pre-eclampsia. The area under the curve (AUC) for both sFlt-1 and PlGF was not different from chance, but combined was 0.55 (P=0.005). Parity and previous diagnosed hypertension had better predictive accuracy than serum biomarkers (AUC=0.64, P<0.001) and the predictive accuracy for all maternal and clinical information was fair (AUC=0.70, P<0.001 for pregnancy hypertension and AUC=0.74, P<0.001 for pre-eclampsia). Adding sFlt-1 and PlGF to maternal risk factors did not improve the ability of the models to predict pregnancy hypertension or pre-eclampsia.ConclusionsMaternal first trimester serum concentrations of sFlt-1 and PlGF do not predict hypertensive disorders in pregnancy any better than routinely collected clinical and maternal risk factor information. Screening for sFlt-1 and PlGF levels in early pregnancy would not identify those pregnancies at-risk

First trimester screening of serum soluble fms-like tyrosine kinase-1 and placental growth factor predicting hypertensive disorders of pregnancy

AbstractObjectiveTo assess the accuracy of first trimester soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) in predicting pregnancy hypertension and pre-eclampsia; and compare with the accuracy of routinely collected maternal and clinical risk factors.Study designIn this population-based cohort study, serum sFlt-1 and PlGF levels were measured in first trimester in 2,681 women with singleton pregnancies in New South Wales, Australia.Main outcome measuresPrediction of pregnancy hypertension and pre-eclampsia.ResultsThere were 213 (7.9%) women with pregnancy hypertension, including 68 (2.5%) with pre-eclampsia. The area under the curve (AUC) for both sFlt-1 and PlGF was not different from chance, but combined was 0.55 (P=0.005). Parity and previous diagnosed hypertension had better predictive accuracy than serum biomarkers (AUC=0.64, P<0.001) and the predictive accuracy for all maternal and clinical information was fair (AUC=0.70, P<0.001 for pregnancy hypertension and AUC=0.74, P<0.001 for pre-eclampsia). Adding sFlt-1 and PlGF to maternal risk factors did not improve the ability of the models to predict pregnancy hypertension or pre-eclampsia.ConclusionsMaternal first trimester serum concentrations of sFlt-1 and PlGF do not predict hypertensive disorders in pregnancy any better than routinely collected clinical and maternal risk factor information. Screening for sFlt-1 and PlGF levels in early pregnancy would not identify those pregnancies at-risk

Angiopoietin 1 and 2 serum concentrations in first trimester of pregnancy as biomarkers of adverse pregnancy outcomes

Objective: To assess Ang-1, Ang-2 and the Ang-1/Ang-2 ratio levels in the first trimester of pregnancy, their association with adverse pregnancy outcomes; and their predictive accuracy. Study Design: This cohort study measured serum Ang-1 and Ang-2 levels in 4,785 women with singleton pregnancies attending first trimester screening in New South Wales, Australia. Multivariate logistic regression models were used to assess the association and predictive accuracy of serum biomarkers with subsequent adverse pregnancy outcomes (small for gestational age, preterm birth, preeclampsia, miscarriage >10 weeks and stillbirth). Results: Median (interquartile range) levels for Ang-1, Ang-2 and the Ang-1/Ang-2 ratio for the total population were 19.6 ng/ml (13.6-26.4), 15.5 ng/ml (10.3-22.7) and 1.21 (0.83-1.73), respectively. Maternal age, weight, country of birth and socio-economic status significantly affected Ang-1, Ang-2 and the Ang-1/Ang-2 ratio levels. After adjusting for maternal and clinical risk factors, women with low Ang-2 levels (90th centile) had increased risk of developing most adverse pregnancy outcomes. Compared to the Ang-1/Ang-2 ratio alone, maternal and clinical risk factors had better predictive accuracy for most adverse pregnancy outcomes. The exception was miscarriage [Ang-1/Ang-2 ratio area under ROC curve (AUC) =0.70; maternal risk factors AUC =0.58]. Overall, adding the Ang-1/Ang-2 ratio to maternal risk factors did not improve the ability of the models to predict adverse pregnancy outcomes. Conclusions: Our findings suggest that the Ang-1/Ang-2 ratio in first trimester is associated with most adverse pregnancy outcomes, but do not predict outcomes any better than clinical and maternal risk factor information.Australian National Health and Medical Research Council (NHMRC) Project Grant (#632653)

Solution of coupled vertex and propagator Dyson-Schwinger equations in the scalar Munczek-Nemirovsky model

In a scalar $\phi^2\chi$ model, we exactly solve the vertex and $\phi$ propagator Dyson-Schwinger equations under the assumption of a spatially constant (Munczek-Nemirovsky) propagator for the $\chi$ field. Various truncation schemes are also considered.Comment: 7 pages,4 figures, minor changes, reference added for published versio

Field theory description of vacuum replicas

In this paper we develop a systematic quantum field theory based approach to the vacuum replica recently found to exist in effective low energy models in hadronic physics. A local operator creating the replica state is constructed explicitly. We show that a new effective quark-quark force arises in result of replica existence. Phenomenological implications of such a force are also briefly discussed.Comment: RevTeX4, 23 pages, 4 Postscript figures, uses epsfig.sty, to appear in Phys.Rev.