1,837 research outputs found

    A slow slip event in the south central Alaska Subduction Zone and related seismicity anomaly

    Get PDF
    Author Posting. © American Geophysical Union, 2012. 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 39 (2012): L15309, doi:10.1029/2012GL052351.We detected a slow slip event in the south central Alaska Subduction Zone by analyzing continuous GPS data from the Plate Boundary Observatory (PBO) network. The slow slip event started in early 2010 at a depth of 35 km beneath the Cook Inlet, near the down-dip end of the locked zone, and is ongoing as of November 2011 with an accumulated magnitude of Mw 6.9. Analysis of the earthquake catalog in the same area using the stochastic Epidemic Type Aftershock Sequence model (ETAS) shows a small but detectable seismicity increase during the slow slip event. We also find a change in seismicity rate around 1998, that may suggest an earlier slow slip event in the same region. Slow slip events in Alaska appear more widespread than previously thought but have remained undetected due to their long durations, the time intervals between them, and the limited time records from the continuous GPS.This research was supported by NSF EarthScope awards 0952174 (MW and JJM) and 0952249 (ER).2013-03-1

    Free drifting buoy trajectories in the Gulf Stream system : 1975-1978 : a data report

    Get PDF
    From 1975 to 1978, thirty-one satellite-tracked free-drifting surface buoys were launched in the Gulf Stream system. Most of these buoys were launched in cyclonic rings, as part of an interdisciplinary Gulf Stream ring experiment, Other buoys were launched in anticyclonic rings and the Gulf Stream itself; one buoy was launched in a cyclonic Kuroshio ring. The basic data set consists of buoy trajectories and sea surface temperature and velocity measurements along trajectories. The main results consist of a series of 19 buoy trajectories in rings from which the movement of rings is inferred and a series of 20 buoy trajectories in the Gulf Stream. Rings frequently coalesced with the Gulf Stream, and some reformed as modified rings. The trajectories of buoys in the Stream reveal that at times surface currents are strongly influenced by topographic features such as seamounts and ridges. Most buoys in the Stream continued to move eastward until they reached the vicinity of the Grand Banks (50°W) where they rapidly fanned out, some moving northward, others eastward across the mid-Atlantic Ridge, still others southward and westward .Prepared for the Office of Naval Research under Contract N00014-74-C-0262; NR 083-004 and for the National Science Foundation under Grants OCE 75-008765 and OCE 77-08045

    Treating Homeless Opioid Dependent Patients with Buprenorphine in an Office-Based Setting

    Get PDF
    CONTEXT Although office-based opioid treatment with buprenorphine (OBOT-B) has been successfully implemented in primary care settings in the US, its use has not been reported in homeless patients. OBJECTIVE To characterize the feasibility of OBOT-B in homeless relative to housed patients. DESIGN A retrospective record review examining treatment failure, drug use, utilization of substance abuse treatment services, and intensity of clinical support by a nurse care manager (NCM) among homeless and housed patients in an OBOT-B program between August 2003 and October 2004. Treatment failure was defined as elopement before completing medication induction, discharge after medication induction due to ongoing drug use with concurrent nonadherence with intensified treatment, or discharge due to disruptive behavior. RESULTS Of 44 homeless and 41 housed patients enrolled over 12 months, homeless patients were more likely to be older, nonwhite, unemployed, infected with HIV and hepatitis C, and report a psychiatric illness. Homeless patients had fewer social supports and more chronic substance abuse histories with a 3- to 6-fold greater number of years of drug use, number of detoxification attempts and percentage with a history of methadone maintenance treatment. The proportion of subjects with treatment failure for the homeless (21%) and housed (22%) did not differ (P=.94). At 12 months, both groups had similar proportions with illicit opioid use [Odds ratio (OR), 0.9 (95% CI, 0.5–1.7) P=.8], utilization of counseling (homeless, 46%; housed, 49%; P=.95), and participation in mutual-help groups (homeless, 25%; housed, 29%; P=.96). At 12 months, 36% of the homeless group was no longer homeless. During the first month of treatment, homeless patients required more clinical support from the NCM than housed patients. CONCLUSIONS Despite homeless opioid dependent patients' social instability, greater comorbidities, and more chronic drug use, office-based opioid treatment with buprenorphine was effectively implemented in this population comparable to outcomes in housed patients with respect to treatment failure, illicit opioid use, and utilization of substance abuse treatment

    Poly(3,4-ethylenedioxythiophene) as a Micro-Neural Interface Material for Electrostimulation

    Get PDF
    Chronic microstimulation-based devices are being investigated to treat conditions such as blindness, deafness, pain, paralysis, and epilepsy. Small-area electrodes are desired to achieve high selectivity. However, a major trade-off with electrode miniaturization is an increase in impedance and charge density requirements. Thus, the development of novel materials with lower interfacial impedance and enhanced charge storage capacity is essential for the development of micro-neural interface-based neuroprostheses. In this report, we study the use of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) as a neural interface material for microstimulation of small-area iridium electrodes on silicon-substrate arrays. Characterized by electrochemical impedance spectroscopy, electrodeposition of PEDOT results in lower interfacial impedance at physiologically relevant frequencies, with the 1 kHz impedance magnitude being 23.3 ± 0.7 kΩ, compared to 113.6 ± 3.5 kΩ for iridium oxide (IrOx) on 177 μm2 sites. Further, PEDOT exhibits enhanced charge storage capacity at 75.6 ± 5.4 mC/cm2 compared to 28.8 ± 0.3 mC/cm2 for IrOx, characterized by cyclic voltammetry (50 mV/s). These improvements at the electrode interface were corroborated by observation of the voltage excursions that result from constant current pulsing. The PEDOT coatings provide both a lower amplitude voltage and a more ohmic representation of the applied current compared to IrOx. During repetitive pulsing, PEDOT-coated electrodes show stable performance and little change in electrical properties, even at relatively high current densities which cause IrOx instability. These findings support the potential of PEDOT coatings as a micro-neural interface material for electrostimulation

    The “fossilized” mitochondrial genome of Liriodendron tulipifera: ancestral gene content and order, ancestral editing sites, and extraordinarily low mutation rate

    Get PDF
    BACKGROUND: The mitochondrial genomes of flowering plants vary greatly in size, gene content, gene order, mutation rate and level of RNA editing. However, the narrow phylogenetic breadth of available genomic data has limited our ability to reconstruct these traits in the ancestral flowering plant and, therefore, to infer subsequent patterns of evolution across angiosperms. RESULTS: We sequenced the mitochondrial genome of Liriodendron tulipifera, the first from outside the monocots or eudicots. This 553,721 bp mitochondrial genome has evolved remarkably slowly in virtually all respects, with an extraordinarily low genome-wide silent substitution rate, retention of genes frequently lost in other angiosperm lineages, and conservation of ancestral gene clusters. The mitochondrial protein genes in Liriodendron are the most heavily edited of any angiosperm characterized to date. Most of these sites are also edited in various other lineages, which allowed us to polarize losses of editing sites in other parts of the angiosperm phylogeny. Finally, we added comprehensive gene sequence data for two other magnoliids, Magnolia stellata and the more distantly related Calycanthus floridus, to measure rates of sequence evolution in Liriodendron with greater accuracy. The Magnolia genome has evolved at an even lower rate, revealing a roughly 5,000-fold range of synonymous-site divergence among angiosperms whose mitochondrial gene space has been comprehensively sequenced. CONCLUSIONS: Using Liriodendron as a guide, we estimate that the ancestral flowering plant mitochondrial genome contained 41 protein genes, 14 tRNA genes of mitochondrial origin, as many as 7 tRNA genes of chloroplast origin, >700 sites of RNA editing, and some 14 colinear gene clusters. Many of these gene clusters, genes and RNA editing sites have been variously lost in different lineages over the course of the ensuing ∽200 million years of angiosperm evolution

    Construction of the descriptive system for the assessment of quality of life AQoL-6D utility instrument

    Get PDF
    BackgroundMulti attribute utility (MAU) instruments are used to include the health related quality of life (HRQoL) in economic evaluations of health programs. Comparative studies suggest different MAU instruments measure related but different constructs. The objective of this paper is to describe the methods employed to achieve content validity in the descriptive system of the Assessment of Quality of Life (AQoL)-6D, MAU instrument.MethodsThe AQoL program introduced the use of psychometric methods in the construction of health related MAU instruments. To develop the AQoL-6D we selected 112 items from previous research, focus groups and expert judgment and administered them to 316 members of the public and 302 hospital patients. The search for content validity across a broad spectrum of health states required both formative and reflective modelling. We employed Exploratory Factor Analysis and Structural Equation Modelling (SEM) to meet these dual requirements.Results and DiscussionThe resulting instrument employs 20 items in a multi-tier descriptive system. Latent dimension variables achieve sensitive descriptions of 6 dimensions which, in turn, combine to form a single latent QoL variable. Diagnostic statistics from the SEM analysis are exceptionally good and confirm the hypothesised structure of the model.ConclusionsThe AQoL-6D descriptive system has good psychometric properties. They imply that the instrument has achieved construct validity and provides a sensitive description of HRQoL. This means that it may be used with confidence for measuring health related quality of life and that it is a suitable basis for modelling utilities for inclusion in the economic evaluation of health programs.<br /

    The very large G-protein coupled receptor VLGR1: a component of the ankle link complex required for the normal development of auditory hair bundles

    Get PDF
    Sensory hair bundles in the inner ear are composed of stereocilia that can be interconnected by a variety of different link types, including tip links, horizontal top connectors, shaft connectors, and ankle links. The ankle link antigen is an epitope specifically associated with ankle links and the calycal processes of photoreceptors in chicks. Mass spectrometry and immunoblotting were used to identify this antigen as the avian ortholog of the very large G-protein-coupled receptor VLGR1, the product of the Usher syndrome USH2C (Mass1) locus. Like ankle links, Vlgr1 is expressed transiently around the base of developing hair bundles in mice. Ankle links fail to form in the cochleae of mice carrying a targeted mutation in Vlgr1 (Vlgr1/del7TM), and the bundles become disorganized just after birth. FM1-43 [N-(3-triethylammonium)propyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] dye loading and whole-cell recordings indicate mechanotransduction is impaired in cochlear, but not vestibular, hair cells of early postnatal Vlgr1/del7TM mutant mice. Auditory brainstem recordings and distortion product measurements indicate that these mice are severely deaf by the third week of life. Hair cells from the basal half of the cochlea are lost in 2-month-old Vlgr1/del7TM mice, and retinal function is mildly abnormal in aged mutants. Our results indicate that Vlgr1 is required for formation of the ankle link complex and the normal development of cochlear hair bundles

    Use of knowledge-based restraints in phenix.refine to improve macromolecular refinement at low resolution

    Get PDF
    Recent developments in PHENIX are reported that allow the use of reference-model torsion restraints, secondary-structure hydrogen-bond restraints and Ramachandran restraints for improved macromolecular refinement in phenix.refine at low resolution

    Graphical tools for macromolecular crystallography in PHENIX.

    Get PDF
    A new Python-based graphical user interface for the PHENIX suite of crystallography software is described. This interface unifies the command-line programs and their graphical displays, simplifying the development of new interfaces and avoiding duplication of function. With careful design, graphical interfaces can be displayed automatically, instead of being manually constructed. The resulting package is easily maintained and extended as new programs are added or modified

    The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management

    Get PDF
    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Staudinger, M. D., Goyert, H., Suca, J. J., Coleman, K., Welch, L., Llopiz, J. K., Wiley, D., Altman, I., Applegate, A., Auster, P., Baumann, H., Beaty, J., Boelke, D., Kaufman, L., Loring, P., Moxley, J., Paton, S., Powers, K., Richardson, D., Robbins, J., Runge, J., Smith, B., Spiegel, C., & Steinmetz, H. The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management. Fish and Fisheries, 00, (2020): 1-34, doi:10.1111/faf.12445.The American sand lance (Ammodytes americanus, Ammodytidae) and the Northern sand lance (A. dubius, Ammodytidae) are small forage fishes that play an important functional role in the Northwest Atlantic Ocean (NWA). The NWA is a highly dynamic ecosystem currently facing increased risks from climate change, fishing and energy development. We need a better understanding of the biology, population dynamics and ecosystem role of Ammodytes to inform relevant management, climate adaptation and conservation efforts. To meet this need, we synthesized available data on the (a) life history, behaviour and distribution; (b) trophic ecology; (c) threats and vulnerabilities; and (d) ecosystem services role of Ammodytes in the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consume Ammodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes, improved assessments of reproductive biology schedules and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food web studies are also needed to evaluate trophic linkages and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the NWA ecosystem. Synthesis results represent the first comprehensive assessment of Ammodytes in the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.This manuscript is the result of follow‐up work stemming from a working group formed at a two‐day multidisciplinary and international workshop held at the Parker River National Wildlife Refuge, Massachusetts in May 2017, which convened 55 experts scientists, natural resource managers and conservation practitioners from 15 state, federal, academic and non‐governmental organizations with interest and expertise in Ammodytes ecology. Support for this effort was provided by USFWS, NOAA Stellwagen Bank National Marine Sanctuary, U.S. Department of the Interior, U.S. Geological Survey, Northeast Climate Adaptation Science Center (Award # G16AC00237), an NSF Graduate Research Fellowship to J.J.S., a CINAR Fellow Award to J.K.L. under Cooperative Agreement NA14OAR4320158, NSF award OCE‐1325451 to J.K.L., NSF award OCE‐1459087 to J.A.R, a Regional Sea Grant award to H.B. (RNE16‐CTHCE‐l), a National Marine Sanctuary Foundation award to P.J.A. (18‐08‐B‐196) and grants from the Mudge Foundation. The contents of this paper are the responsibility of the authors and do not necessarily represent the views of the National Oceanographic and Atmospheric Administration, U.S. Fish and Wildlife Service, New England Fishery Management Council and Mid‐Atlantic Fishery Management Council. This manuscript is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints for Governmental purposes. Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government
    corecore