1,489 research outputs found

    Juan de Fuca subduction zone from a mixture of tomography and waveform modeling

    Get PDF
    Seismic tomography images of the upper mantle structures beneath the Pacific Northwestern United States display a maze of high-velocity anomalies, many of which produce distorted waveforms evident in the USArray observations indicative of the Juan de Fuca (JdF) slab. The inferred location of the slab agrees quite well with existing contour lines defining the slab's upper interface. Synthetic waveforms generated from a recent tomography image fit teleseismic travel times quite well and also some of the waveform distortions. Regional earthquake data, however, require substantial changes to the tomographic velocities. By modeling regional waveforms of the 2008 Nevada earthquake, we find that the uppermost mantle of the 1D reference model AK135, the reference velocity model used for most tomographic studies, is too fast for the western United States. Here, we replace AK135 with mT7, a modification of an older Basin-and-Range model T7. We present two hybrid velocity structures satisfying the waveform data based on modified tomographic images and conventional slab wisdom. We derive P and SH velocity structures down to 660 km along two cross sections through the JdF slab. Our results indicate that the JdF slab is subducted to a depth of 250 km beneath the Seattle region, and terminates at a shallower depth beneath Portland region of Oregon to the south. The slab is about 60 km thick and has a P velocity increase of 5% with respect to mT7. In order to fit waveform complexities of teleseismic Gulf of Mexico and South American events, a slab-like high-velocity anomaly with velocity increases of 3% for P and 7% for SH is inferred just above the 660 discontinuity beneath Nevada

    Upper mantle P velocity structure beneath the Midwestern United States derived from triplicated waveforms

    Get PDF
    Upper mantle seismic velocity structures in both vertical and horizontal directions are key to understanding the structure and mechanics of tectonic plates. Recent deployment of the USArray Transportable Array (TA) in the Midwestern United States provides an extraordinary regional earthquake data set to investigate such velocity structure beneath the stable North American craton. In this paper, we choose an M_w5.1 Canadian earthquake in the Quebec area, which is recorded by about 400 TA stations, to examine the P wave structures between the depths of 150 km to 800 km. Three smaller Midwestern earthquakes at closer distance to the TA are used to investigate vertical and horizontal variations in P velocity between depths of 40 km to 150 km. We use a grid-search approach to find the best 1-D model, starting with the previously developed S25 regional model. The results support the existence of an 8° discontinuity in P arrivals caused by a negative velocity gradient in the lithosphere between depths of 40 km to 120 km followed by a small (∼1%) jump and then a positive gradient down to 165 km. The P velocity then decreases by 2% from 165 km to 200 km, and we define this zone as the regional lithosphere-asthenosphere boundary (LAB). Beneath northern profiles, waves reflected from the 410 discontinuity (410) are delayed by up to 1 s relative to those turning just below the 410, which we explain by an anomaly just above the discontinuity with P velocity reduced by ∼3%. The 660 discontinuity (660) appears to be composed of two smaller velocity steps with a separation of 16 km. The inferred low-velocity anomaly above 410 may indicate high water concentrations in the transition zone, and the complexity of the 660 may be related to Farallon slab segments that have yet to sink into the deep mantle

    The 2008 flexAbility Toolkit

    Get PDF
    The flexAbility manual contains almost 200 pages of resources developed specifically to support Oregon employers. The key chapters include:* Introduction* A matter of respect* Employment strategies* Vocational rehabilitation* Financial incentives and Oregon Programs* Workplace accommodations* Real people, real jobs: Situations and solutions* Disability legislation* Small Business Guide: The ADA* Glossary of commonly used terms* Employer resource guid

    Making Round Bale Silage – Lessons Learned From an On-Farm Survey of Baleage in Kentucky

    Get PDF
    The ability to make silage in round bale packages allows producers to avoid rain damage and produce high quality stored forage. The proliferation of bale wrappers (both individual and inline types) has made this technology more available to producers. Although the process for making baleage is well documented, producers have experienced poor fermentation and in some cases botulism toxicity from baleage. The parameters of good silage are well known and include pH below 5.0 and lactic acid concentrations above 3% on a DM basis. However, tests of farmer- produced baleage reveals that often these target values are not achieved. To better understand the fermentation characteristics of Kentucky baleage, a survey was conducted of round bale silage samples from several Kentucky counties in 2017, 2018 and 2019. Moisture content (MC) at baling was the greatest determinant of fermentation success as measured by pH and lactic acid concentration. Moisture contents were highly variable, with more outside the recommended range of MC (40 to 60%) than within. Farmer practices including wilting time and equipment used were recorded for the 2019 samples. All the well-accepted practices for making baleage were confirmed in this survey (cutting on time, wilting to proper MC, dense bales, achieving and maintaining anaerobic storage conditions). Baleage samples exceeding 65% MC had elevated butyric acid concentrations, indicating secondary fermentation by clostridial bacteria

    Round Bale Silage – Farmer Results in Kentucky

    Get PDF
    The ability to make silage in round bale packages allows producers to avoid rain damage and produce high quality stored forage. The proliferation of bale wrappers (both individual and inline types) has made this technology more available to producers. Although the process for making baleage is well documented, producers have experienced poor fermentation and in some cases botulism toxicity from baleage. The parameters of good silage are well known and include pH below 5.0 and lactic acid concentrations above 3% on a DM basis. However, tests of farmer produced baleage reveals that often these target values are not achieved. To better understand the fermentation characteristics of Kentucky baleage, a survey was conducted of round bale silage samples from several Kentucky counties in 2017, 2018 and 2019. Moisture content (MC) at baling was the greatest determinant of fermentation success as measured by pH and lactic acid concentration. Moisture contents were highly variable, with more outside the recommended range of MC (40 to 60%) than within. Farmer practices including wilting time and equipment used were recorded for the 2019 samples. All of the well‐accepted practices for making baleage were confirmed in this survey (cutting on time, wilting to proper MC, dense bales, achieving and maintaining anaerobic storage conditions). Baleage samples exceeding 65% MC had elevated butyric acid concentrations, indicating secondary fermentation by clostridial bacteria

    Potent spinal parenchymal AAV9-mediated gene delivery by subpial injection in adult rats and pigs.

    Get PDF
    Effective in vivo use of adeno-associated virus (AAV)-based vectors to achieve gene-specific silencing or upregulation in the central nervous system has been limited by the inability to provide more than limited deep parenchymal expression in adult animals using delivery routes with the most clinical relevance (intravenous or intrathecal). Here, we demonstrate that the spinal pia membrane represents the primary barrier limiting effective AAV9 penetration into the spinal parenchyma after intrathecal AAV9 delivery. We develop a novel subpial AAV9 delivery technique and AAV9-dextran formulation. We use these in adult rats and pigs to show (i) potent spinal parenchymal transgene expression in white and gray matter including neurons, glial and endothelial cells after single bolus subpial AAV9 delivery; (ii) delivery to almost all apparent descending motor axons throughout the length of the spinal cord after cervical or thoracic subpial AAV9 injection; (iii) potent retrograde transgene expression in brain motor centers (motor cortex and brain stem); and (iv) the relative safety of this approach by defining normal neurological function for up to 6 months after AAV9 delivery. Thus, subpial delivery of AAV9 enables gene-based therapies with a wide range of potential experimental and clinical utilizations in adult animals and human patients

    Effects of Endotracheal Administration of Epinephrine in Cardiac Arrest of Adult and Pediatric Swine

    Get PDF
    BACKGROUND: Few studies have investigated the effects of hypovolemia on area under the curve (AUC) and the return of spontaneous circulation (ROSC) comparing adults and children in cardiac arrest.AIMS: To compare the epinephrine endotracheal (ET) administration relative to AUC, rate, time to, and odds of achieving ROSC between hypovolemic adult and pediatric cardiac arrest models.METHODS: This was an experimental study using male Adult ET and Pediatric ET swine. Pediatric ET pigs (N=7) weighed 20-30 kg representing the average weight for a child between 5 and 6 years of age. Adult ET pigs (N=7) weighed 60 to 80 kg. All were exsanguinated 35% of their blood volume. Swine were put into arrest for 2 minutes. Cardiopulmonary resuscitation (CPR) was initiated for 2 minutes; epinephrine was then administered. Blood samples were collected over 5 minutes. RESULTS: No significant difference occurred in AUC between the groups (p > 0.05). The Pediatric ET group had higher rates of ROSC and a shorter time to ROSC (p < 0.05). Pediatric ET group had a 15 times greater odds of achieving ROSC compared to the Adult ET group. CONCLUSION: Based on the results of this study, we recommend epinephrine administration via ET within the pediatric arrest model, but not for the adult

    Forgiveness-Reconciliation and Communication-Conflict-Resolution Interventions Versus Retested Controls in Early Married Couples

    Get PDF
    The first 6 months of marriage are optimal for marriage enrichment interventions. The Hope-Focused Approach to couple enrichment was presented as two 9-hr interventions--(a) Handling Our Problems Effectively (HOPE), which emphasized communication and conflict resolution, and (b) Forgiveness and Reconciliation through Experiencing Empathy (FREE). HOPE and FREE were compared with repeated assessment controls. Couples were randomly assigned and were assessed at pretreatment (t1); 1 month posttreatment (t2) and at 3- (t3), 6- (t4), and 12-month (t5) follow-ups using self-reports. In addition to self-report measures, couples were assessed at t1, t2, and t5 using salivary cortisol, and behavioral coding of decision making. Of 179 couples who began the study, 145 cases were analyzed. Both FREE and HOPE produced lasting positive changes on self-reports. For cortisol reactivity, HOPE and FREE reduced reactivity at t2, but only HOPE at t5. For coded behaviors, control couples deteriorated; FREE and HOPE did not change. Enrichment training was effective regardless of the focus of the training
    corecore