Geomorphic process fingerprints in submarine canyons

This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 337 (2013): 53-66, doi:10.1016/j.margeo.2013.01.005.Submarine canyons are common features of continental margins worldwide. They are conduits that funnel vast quantities of sediment from the continents to the deep sea. Though it is known that submarine canyons form primarily from erosion induced by submarine sediment flows, we currently lack quantitative, empirically based expressions that describe the morphology of submarine canyon networks. Multibeam bathymetry data along the entire passive US Atlantic margin (USAM) and along the active central California margin near Monterey Bay provide an opportunity to examine the fine-scale morphology of 171 slope-sourced canyons. Log–log regression analyses of canyon thalweg gradient (S) versus up-canyon catchment area (A) are used to examine linkages between morphological domains and the generation and evolution of submarine sediment flows. For example, canyon reaches of the upper continental slope are characterized by steep, linear and/or convex longitudinal profiles, whereas reaches farther down canyon have distinctly concave longitudinal profiles. The transition between these geomorphic domains is inferred to represent the downslope transformation of debris flows into erosive, canyon-flushing turbidity flows. Over geologic timescales this process appears to leave behind a predictable geomorphic fingerprint that is dependent on the catchment area of the canyon head. Catchment area, in turn, may be a proxy for the volume of sediment released during geomorphically significant failures along the upper continental slope. Focused studies of slope-sourced submarine canyons may provide new insights into the relationships between fine-scale canyon morphology and down-canyon changes in sediment flow dynamics

Deformation of the Pacific/North America plate boundary at Queen Charlotte Fault : the possible role of rheology

Published 2018. This article is a U.S. Government work and is in the public domain in the USA. The definitive version was published in Journal of Geophysical Research: Solid Earth 123 (2018): 4223-4242, doi:10.1002/2017JB014770.The Pacific/North America (PA/NA) plate boundary between Vancouver Island and Alaska is similar to the PA/NA boundary in California in its kinematic history and the rate and azimuth of current relative motion, yet their deformation styles are distinct. The California plate boundary shows a broad zone of parallel strike slip and thrust faults and folds, whereas the 49‐mm/yr PA/NA relative plate motion in Canada and Alaska is centered on a single, narrow, continuous ~900‐km‐long fault, the Queen Charlotte Fault (QCF). Using gravity analysis, we propose that this plate boundary is centered on the continent/ocean boundary (COB), an unusual location for continental transform faults because plate boundaries typically localize within the continental lithosphere, which is weaker. Because the COB is a boundary between materials of contrasting elastic properties, once a fault is established there, it will probably remain stable. We propose that deformation progressively shifted to the COB in the wake of Yakutat terrane's northward motion along the margin. Minor convergence across the plate boundary is probably accommodated by fault reactivation on Pacific crust and by an eastward dipping QCF. Underthrusting of Pacific slab under Haida Gwaii occurs at convergence angles >14°–15° and may have been responsible for the emergence of the archipelago. The calculated slab entry dip (5°–8°) suggests that the slab probably does not extend into the asthenosphere. The PA/NA plate boundary at the QCF can serve as a structurally simple site to investigate the impact of rheology and composition on crustal deformation and the initiation of slab underthrusting

Geologic controls on submarine slope failure along the central U.S. Atlantic margin : insights from the Currituck Slide Complex

© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Geology 385 (2017): 114-130, doi:10.1016/j.margeo.2016.10.007.Multiple styles of failure, ranging from densely spaced, mass transport driven canyons to the large, slab-type slope failure of the Currituck Slide, characterize adjacent sections of the central U.S. Atlantic margin that appear to be defined by variations in geologic framework. Here we use regionally extensive, deep penetration multichannel seismic (MCS) profiles to reconstruct the influence of the antecedent margin physiography on sediment accumulation along the central U.S. Atlantic continental shelf-edge, slope, and uppermost rise from the Miocene to Present. These data are combined with highresolution sparker MCS reflection profiles and multibeam bathymetry data across the Currituck Slide complex. Pre-Neogene allostratigraphic horizons beneath the slope are generally characterized by low gradients and convex downslope profiles. This is followed by the development of thick, prograded deltaic clinoforms during the middle Miocene. Along-strike variations in morphology of a regional unconformity at the top of this middle Miocene unit appear to have set the stage for differing styles of mass transport along the margin. Areas north and south of the Currituck Slide are characterized by oblique margin morphology, defined by an angular shelf-edge and a relatively steep (>8°), concave slope profile. Upper slope sediment bypass, closely spaced submarine canyons, and small, localized landslides confined to canyon heads and sidewalls characterize these sectors of the margin. In contrast, the Currituck region is defined by a sigmoidal geometry, with a rounded shelf-edge rollover and gentler slope gradient (<6°). Thick (>800 m), regionally continuous stratified slope deposits suggest the low gradient Currituck region was a primary depocenter for fluvial inputs during multiple sea level lowstands. These results imply that the rounded, gentle slope physiography developed during the middle Miocene allowed for a relatively high rate of subsequent sediment accumulation, thus providing a mechanism for compaction–induced overpressure that preconditioned the Currituck region for failure. Detailed examination of the regional geological framework illustrates the importance of both sediment supply and antecedent slope physiography in the development of large, potentially unstable depocenters along passive margins.The U.S. Geological Survey, the U.S. Nuclear Regulatory Commission and Coastal Carolina University funded this research

Seabed fluid expulsion along the upper slope and outer shelf of the U.S. Atlantic continental margin

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 41 (2014): 96-101, doi:10.1002/2013GL058048.Identifying the spatial distribution of seabed fluid expulsion features is crucial for understanding the substrate plumbing system of any continental margin. A 1100 km stretch of the U.S. Atlantic margin contains more than 5000 pockmarks at water depths of 120 m (shelf edge) to 700 m (upper slope), mostly updip of the contemporary gas hydrate stability zone (GHSZ). Advanced attribute analyses of high-resolution multichannel seismic reflection data reveal gas-charged sediment and probable fluid chimneys beneath pockmark fields. A series of enhanced reflectors, inferred to represent hydrate-bearing sediments, occur within the GHSZ. Differential sediment loading at the shelf edge and warming-induced gas hydrate dissociation along the upper slope are the proposed mechanisms that led to transient changes in substrate pore fluid overpressure, vertical fluid/gas migration, and pockmark formation.The U.S. Geological Survey and the U.S. Nuclear Regulatory Commission funded this research.2014-07-0

Results of 1992 seismic reflection experiment in Lake Baikal

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95684/1/eost9857.pd

Impact of borderline personality disorder traits on the association between age and health-related quality of life:A cohort study in the general population

Background Increasing age as well as borderline personality pathology are associated with a lower level of health-related quality of life (HR-QoL). Our objective was to investigate whether the presence of borderline personality traits modifies the association between age and HR-QoL in the general population. Methods Cross-sectional data from 5,303 respondents (aged 21-72 years) of the Netherlands Mental Health Survey and Incidence Study-2 were analyzed. Borderline personality traits were assessed with the International Personality Disorder Examination questionnaire. Mental and physical HR-QoL were measured with the Medical Outcomes Study Short Form Health Survey. Multiple linear regression analysis was used to examine the association of borderline personality traits, age and their interaction on mental as well as physical HR-QoL, adjusted for demographic variables as well as somatic and mental disorders. Results A total of 1,520 (28.7%) respondents reported one or more borderline personality traits of which 58 (1.1%) reported five or more indicative of a borderline personality disorder. A higher age was associated with lower physical HR-QoL. This negative association became significantly stronger in the presence of borderline personality traits. The association between increasing age and mental HR-QoL was positive in the absence of borderline personality traits and negative in the presence of borderline personality traits. Conclusion Borderline personality traits negatively interfere with the association between age and HR-QoL irrespective of somatic and mental disorders. Attention of clinicians and researchers for subthreshold borderline personality pathology is needed in middle-aged and older persons

High interpatient variability of treosulfan exposure is associated with early toxicity in paediatric HSCT: a prospective multicentre study

Treosulfan-based conditioning is increasingly employed in paediatric haematopoietic stem cell transplantation (HSCT). Data on treosulfan pharmacokinetics in children are scarce, and the relationship between treosulfan exposure, toxicity and clinical outcome is unresolved. In this multicentre prospective observational study, we studied treosulfan pharmacokinetics and the drug's relationship with regimen-related toxicity and early clinical outcome in 77 paediatric patients. Treosulfan dose was 30&nbsp;g/m2, administered over 3 consecutive days in infants &lt;1&nbsp;year old (n&nbsp;=&nbsp;12) and 42&nbsp;g/m2 in children ≥1&nbsp;year old (n&nbsp;=&nbsp;65). Mean day 1 treosulfan exposure was 1744&nbsp;±&nbsp;795&nbsp;mg*h/l (10&nbsp;g/m2) and 1561&nbsp;±&nbsp;511&nbsp;mg*h/l (14&nbsp;g/m2), with an inter-individual variability of 56 and 33% in the respective groups. High treosulfan exposure (&gt;1650&nbsp;mg*h/l) was associated with an increased risk of mucosal [Odds ratio (OR) 4·40; 95% confidence interval (CI) 1·19–16·28, P&nbsp;=&nbsp;0·026] and skin toxicity (OR 4·51; 95% CI 1·07–18·93, P&nbsp;=&nbsp;0·040). No correlation was found between treosulfan exposure and the early clinical outcome parameters: engraftment, acute graft-versus-host disease and donor chimerism. Our study provides the first evidence in a large cohort of paediatric patients of high variability in treosulfan pharmacokinetics and an association between treosulfan exposure and early toxicity. Ongoing studies will reveal whether treosulfan exposure is related to long-term disease-specific outcome and late treatment-related toxicity

A survey of three-dimensional turbo codes and recent performance enhancements

This paper presents a survey of two techniques intended for improving the performance of conventional turbo codes (TCs). The first part of this work is dedicated to explore a hybrid concatenation structure combining both parallel and serial concatenation based on a three-dimensional (3D) code. The 3D structure, recently introduced by Berrou et al., is able to ensure large asymptotic gains at very low error rates at the expense of an increase in complexity and a loss in the convergence threshold. In order to reduce the loss in the convergence threshold, the authors consider first a time-varying construction of the post-encoded parity. Then, they investigate the association of the 3D TC with high-order modulations according to the bit-interleaved coded modulation approach. The second part of this study deals with irregular TCs. In contrast to 3D TCs, although irregular TCs can achieve performance closer to capacity, their asymptotic performance is very poor. Therefore, the authors propose irregular turbo coding schemes with suitable interleavers in order to improve their distance properties. Finally, a modified encoding procedure, inspired from the 3D TC, makes it possible to obtain irregular TCs which perform better than the corresponding regular codes in both the waterfall and the error floor regions

Health and economic benefits of achieving contraceptive and maternal health targets in small island developing states in the Pacific and Caribbean

INTRODUCTION: Reducing unmet need for modern contraception and expanding access to quality maternal health (MH) services are priorities for improving women's health and economic empowerment. To support investment decisions, we estimated the additional cost and expected health and economic benefits of achieving the United Nations targets of zero unmet need for modern contraceptive choices and 95% coverage of MH services by 2030 in select Small Island Developing States. METHODS: Five Pacific (Kiribati, Samoa, Solomon Islands, Tonga and Vanuatu) and four Caribbean (Barbados, Guyana, Jamaica and Saint Lucia) countries were considered based on population survey data availability. For each country, the Lives Saved Tool was used to model costs, health outcomes and economic benefits for two scenarios: business-as-usual (BAU) (coverage maintained) and coverage-targets-achieved, which scaled linearly from 2022 (following COVID-19 disruptions) coverage of evidence-based family planning and MH interventions to reach United Nations targets, including modern contraceptive methods and access to complete antenatal, delivery and emergency care. Unintended pregnancies, maternal deaths, stillbirths and newborn deaths averted by the coverage-targets-achieved scenario were converted to workforce, education and social economic benefits; and benefit-cost ratios were calculated. RESULTS: The coverage-targets-achieved scenario required an additional US$12.6M (US$10.8M-US$15.9M) over 2020-2030 for the five Pacific countries (15$82.4M to maintain BAU). This additional investment was estimated to avert 126 000 (40%) unintended pregnancies, 2200 (28%) stillbirths and 121 (29%) maternal deaths and lead to a 15-fold economic benefit of US$190.6M (US$67.0M-US$304.5M) by 2050. For the four Caribbean countries, an additional US$17.8M (US$15.3M-US$22.4M) was needed to reach the targets (4% more than US$405.4M to maintain BAU). This was estimated to avert 127 000 (23$426.2M (US$138.6M-US$745.7M) by 2050. CONCLUSION: Achieving full coverage of contraceptive and MH services in the Pacific and Caribbean is likely to have a high return on investment