61 research outputs found

    Timing and Nature of Post-Collapse Sedimentation in Kulshan Caldera, North Cascades, Washington

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    Sedimentary rocks found in the 4.5 x 8 km Kulshan caldera of the Mount Baker volcanic field in the North Cascades, WA, indicate that the post-collapse basin hosted a lacustrine environment shortly after the initial collapse at 1.149 Ma (Hildreth, 1996). The sedimentary rocks of the 14 Goat area in Kulshan caldera are well-preserved in 124 meters of stratigraphic exposure. Blocks of wall rock debris in the lower stratigraphy show instability in the caldera wall. Intermediate and late stages are mainly turbidites composed primarily of sediments derived from extra-caldera ignimbrite. From these 1 interpret the 14 Goat area of Kulshan to have been a steep and deep depositional basin for most of its history. Additional sedimentary structures found in Kulshan caldera reveal a complex environmental history. Trough cross-bedding within a well sorted sandstone indicates channelized flow. Clastic dikes resulted from the overburdening of wet sediments. Dropstones found throughout the stratigraphy indicate an active ice field. Outside the stratigraphic section but within the 14 Goat area oscillation ripples indicate shallow water and raindrop imprints show drying. Paleomagnetic analysis of 12 sites spanning the entire stratigraphic column failed to show that any magnetic transition was recorded in the Kulshan sediments. Anisotropy of magnetic susceptibility results confirm that grain settling from quiet water produced the most prominent magnetic fabric and confirm secondary alteration was likely the cause of scatter in the remanent magnetization signal. A conservative estimate for the duration of the lacustrine environment at Kulshan caldera is 157 ka leading to a minimum rate of sedimentation of 79 cm/ka. A shorter estimate suggests duration of 22 ka and rate of sedimentation of 560 cm/ka. The sedimentary environments of Kulshan caldera are similar to other calderas with post-collapse depositional records. Kulshan caldera compares favorably to depositional models for small calderas (less than 10 km)

    Noradrenergic Pharmacotherapy, Intracerebral Infusion and Adrenal Transplantation Promote Functional Recovery After Cortical Damage

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    The research described in this review briefly summarizes evidence that short term pharmacological enhancement of noradrenergic (NA) synaptic activity, combined with symptom relevant experience (SRE), promotes functional recovery of some symptoms of cortical damage in rat, cat and human beings even when treatment is initiated from days to weeks after injury. A summary is provided of the numerous drugs tested in rodent cortical injury models which have been proven useful for predicting beneficial or harmful effects on behavioral outcome in human stroke. The pattern of drug effects indicates a central role for NA in functional recovery. Additionally, studies of the effects of direct intraventricular infusion of monoamine neurotransmitters are reviewed and further support the hypothesized role of NA in recovery from some symptoms of cortical injury. The site of NA/SRE interaction to promote recovery from hemiplegia apparently involves the cerebellar hemisphere contralateral to the cortical injury. Microinfusions of NA into the contra- but not ipsilaterai cerebellar hemisphere dramatically enhance recovery. Furthermore, like its systemic action, microinfusion of the α1- NA receptor antagonist, phenoxybenzamine, reinstates hemiplegia. A “permanent” symptom of motor cortex injury in the cat is the complete loss of tactile placing contralateral to the injury which does not spontaneously recover for as long as seven years after ablation. This posturai reflex is temporarily restored for 8-12 hours following amphetamine administration. However, this permanently lost reflex can be enduringly restored by transplanting catecholamine secreting adrenal tissue into the wound cavity. The experiment is reviewed in detail and involves chromaffin cell autografts into the frontal cortex ablation wound cavity producing a restoration of tactile placing for the 7-10 month duration of the study. This enduring restoration of tactile placing is considered a result of the release of catecholamines into the CNS from the grafted chromaffin cells found, by histochemical methods, surviving 7-10 months after transplant. Lastly, we attribute these delayed treatment effects to an attenuation of a diaschisis, or remote functional depression, in morphologically intact areas anatomically connected to the area of injury. The widespread reduction of glycolytic and oxidative metabolism, produced by focal cortical injury, is normalized by the same treatment which alleviates symptoms and is worsened by drugs which exacerbate deficits. These data support the hypothesis that providing SRE during a period of enhanced NA synaptic activity produces an enduring functional recovery after cortical injury by attenuating remote functional depression. This treatment for enhancing recovery is especially attractive since it is effective even when begun weeks after cortical damage

    Alleviation of Brain Injury-Induced Cerebral Metabolic Depression by Amphetamine: A Cytochrome Oxidase Histochemistry Study

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    Measurements of oxidative metabolic capacity following the ablation of rat sensorimotor cortex and ,he administration of amphetamine were examined to determine their effects on the metabolic dysfunction that follows brain injury. Twenty-four hours after surgery, rats sustaining either sham operations or unilateral cortical ablation were administered a single injection of D-amphetamine (2 mg/kg; i.p.) or saline and then sacrificed 24 h later. Brain tissue was processed for cytochrome oxidase histochemistry, and 12 bilateral cerebral areas were measured, using optical density as an index of the relative amounts of the enzyme. Compared with that of the control groups, cytochrome oxidase in the injured animals was significantly reduced throughout the cerebral cortex and in 5 of II subcortical structures. This injury-induced depression of oxidative capacity was most pronounced in regions of the hemisphere ipsilateral to the ablation. Animals given D-amphetamine had less depression of oxidative capacity, which was most pronounced bilaterally in the cerebral cortex, red nucleus, and superior colliculus; and in the nucleus accumbens, caudateputamen, and globus pallidus ipsilaterai to the ablation. The ability of D-amphetamine to alleviate depressed cerebral oxidative metabolism following cortical injury may be one mechanism by which drugs increasing noradrenaline release accelerate functional recovery in both animals and humans

    U–Pb Zircon Ages, Mapping, and Biostratigraphy of the Payette Formation and Idaho Group North of the Western Snake River Plain, Idaho: Implications for Hydrocarbon System Correlation

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    Sedimentary deposits north of the western Snake River Plain host Idaho’s first and only producing oil and gas field. They consist of the lower to middle Miocene Payette Formation, the middle to upper Miocene Poison Creek and Chalk Hills Formations, and the Pliocene to lower Pleistocene Glenns Ferry Formation. Using new geochronology, palynomorph biostratigraphy, and geologic mapping, we connect updip surface features to subsurface petroleum play elements. The Payette Formation is a likely main source of the hydrocarbons, and acts as one of the reservoirs in the unnamed basin. Here, we redefine the Payette Formation as 0 to ~3,500 ft (0 to ~1,000 m) of mudstone, with lesser amounts of sandstone overlying and interbedded with the Columbia River Basalt Group and Weiser volcanic field. Index palynomorphs, including Liquidambar and Pterocarya, present in Idaho during and immediately after the middle Miocene climatic optimum, and new U–Pb ages of 16.39 and 15.88 Ma, help establish the thickness and extent of the formation. For the first time, these biostratigraphic markers have been defined for the oil and gas wells. The Poison Creek Formation is sandstone interbedded with mudstone that is ~800–1,800 ft (250–550 m) thick. The Chalk Hills Formation is a tuffaceous siltstone, claystone, and sandstone that is as much as ~4,200 ft (1,280 m) thick. New U–Pb ages are 10.1, 9.04, and 9.00 for the Poison Creek Formation, along with maximum depositional ages of 10.7 to 9.9 Ma for four samples from the Poison Creek Formation. A single U–Pb age of 7.78 Ma was determined from pumice low in the Chalk Hills Formation. Like the Payette Formation, the Poison Creek Formation can be a reservoir, whereas the Chalk Hills Formation acts as a sealing mudstone facies. The overlying sandstone, siltstone, and conglomerate of the Glenns Ferry Formation act as the overburden to the petroleum system in the subsurface, and were important for burial and hydrocarbon maturation. The Glenns Ferry Formation is up to 500 ft (150 m) thick in the study area, as much has been eroded. Whereas the Payette and Poison Creek Formations were deposited during the mid-Miocene climatic optimum amongst and above volcanic flows, the Chalk Hills and Glenns Ferry Formations were deposited within ancient Lake Idaho during an overall increase in aridity and cooling after the mid-Miocene climatic optimum

    Identifying Otosclerosis with Aural Acoustical Tests of Absorbance, Group Delay, Acoustic Reflex Threshold, and Otoacoustic Emissions

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    Background: Otosclerosis is a progressive middle-ear disease that affects conductive transmission through the middle ear. Ear-canal acoustic tests may be useful in the diagnosis of conductive disorders. This study addressed the degree to which results from a battery of ear-canal tests, which include wideband reflectance, acoustic stapedius muscle reflex threshold (ASRT), and transient evoked otoacoustic emissions (TEOAEs), were effective in quantifying a risk of otosclerosis and in evaluating middle-ear function in ears after surgical intervention for otosclerosis. Purpose: To evaluate the ability of the test battery to classify ears as normal or otosclerotic, measure the accuracy of reflectance in classifying ears as normal or otosclerotic, and evaluate the similarity of responses in normal ears compared with ears after surgical intervention for otosclerosis. Research Design: A quasi-experimental cross-sectional study incorporating case control was used. Three groups were studied: one diagnosed with otosclerosis before corrective surgery, a group that received corrective surgery for otosclerosis, and a control group. Study Sample: The test groups included 23 ears (13 right and 10 left) with normal hearing from 16 participants (4 male and 12 female), 12 ears (7 right and 5 left) diagnosed with otosclerosis from 9 participants (3 male and 6 female), and 13 ears (4 right and 9 left) after surgical intervention from 10 participants (2 male and 8 female). Data Collection and Analysis: Participants received audiometric evaluations and clinical immittance testing. Experimental tests performed included ASRT tests with wideband reference signal (0.25–8 kHz), reflectance tests (0.25–8 kHz), which were parameterized by absorbance and group delay at ambient pressure and at swept tympanometric pressures, and TEOAE tests using chirp stimuli (1–8 kHz). ASRTs were measured in ipsilateral and contralateral conditions using tonal and broadband noise activators. Experimental ASRT tests were based on the difference in wideband-absorbed sound power before and after presenting the activator. Diagnostic accuracy to classify ears as otosclerotic or normal was quantified by the area under the receiver operating characteristic curve (AUC) for univariate and multivariate reflectance tests. The multivariate predictor used a small number of input reflectance variables, each having a large AUC, in a principal components analysis to create independent variables and followed by a logistic regression procedure to classify the test ears. Results:Relative to the results in normal ears, diagnosed otosclerosis earsmore frequently showed absent TEOAEs and ASRTs, reduced ambient absorbance at 4 kHz, and a different pattern of tympanometric absorbance and group delay (absorbance increased at 2.8 kHz at the positive-pressure tail and decreased at 0.7–1 kHz at the peak pressure, whereas group delay decreased at positive and negative-pressure tails from 0.35–0.7 kHz, and at 2.8–4 kHz at positive-pressure tail). Using a multivariate predictor with three reflectance variables, tympanometric reflectance (AUC 5 0.95) was more accurate than ambient reflectance (AUC 5 0.88) in classifying ears as normal or otosclerotic. Conclusions: Reflectance provides a middle-ear test that is sensitive to classifying ears as otosclerotic or normal, which may be useful in clinical applications

    A touchdown nucleic acid amplification protocol as an alternative to culture backup for immunofluorescence in the routine diagnosis of acute viral respiratory tract infections

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    BACKGROUND: Immunofluorescence and virus culture are the main methods used to diagnose acute respiratory virus infections. Diagnosing these infections using nucleic acid amplification presents technical challenges, one of which is facilitating the different optimal annealing temperatures needed for each virus. To overcome this problem we developed a diagnostic molecular strip which combined a generic nested touchdown protocol with in-house primer master-mixes that could recognise 12 common respiratory viruses. RESULTS: Over an 18 month period a total of 222 specimens were tested by both immunofluorescence and the molecular strip. The specimens came from 103 males (median age 3.5 y), 80 females (median age 9 y) and 5 quality assurance scheme specimens. Viruses were recovered from a number of specimen types including broncho-alveolar lavage, nasopharyngeal secretions, sputa, post-mortem lung tissue and combined throat and nasal swabs. Viral detection by IF was poor in sputa and respiratory swabs. A total of 99 viruses were detected in the study from 79 patients and 4 quality control specimens: 31 by immunofluorescence and 99 using the molecular strip. The strip consistently out-performed immunofluorescence with no loss of diagnostic specificity. CONCLUSIONS: The touchdown protocol with pre-dispensed primer master-mixes was suitable for replacing virus culture for the diagnosis of respiratory viruses which were negative by immunofluorescence. Results by immunofluorescence were available after an average of 4–12 hours while molecular strip results were available within 24 hours, considerably faster than viral culture. The combined strip and touchdown protocol proved to be a convenient and reliable method of testing for multiple viruses in a routine setting

    Health-related quality of life in adults reporting arthritis: analysis from the National Health Measurement Study

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    BackgroundArthritis is the leading cause of disability in the United States. We assess the generic health-related quality-of-life (HRQOL) among a nationally representative sample of U.S. adults with and without self-reported arthritis.MethodsThe NHMS, a cross-sectional survey of 3,844 adults (35-89 years) administered EuroQol-5D (EQ-5D), Health Utilities Index Mark 2 (HUI2) and 3 (HUI3), SF-36v2ℱ, Quality of Well-being Scale self-administered form (QWB-SA), and the Health and Activities Limitations index (HALex) to each respondent via a telephone interview. Weighted multiple linear regression was used to generate age-gender-arthritis-stratified unadjusted HRQOL means and means adjusted for sociodemographic, socioeconomic covariates and comorbidities by arthritis-age category.ResultsThe estimated population prevalence of self-reported arthritis was 31%. People with arthritis were more likely to be woman, older, of lower socioeconomic status, and had more self-reported comorbidities than were those not reporting arthritis. Adults with arthritis had lower HRQOL on six different indexes compared with adults without arthritis, with overall differences ranging from 0.03 (QWB-SA, age-group 65-74) to 0.17 (HUI3, age-group 35-44; all P-value < .05).ConclusionArthritis in adults is associated with poorer HRQOL. We provide age-related reference values for six generic HRQOL measures in people with arthritis

    Postpartum psychiatric disorders

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    Pregnancy is a complex and vulnerable period that presents a number of challenges to women, including the development of postpartum psychiatric disorders (PPDs). These disorders can include postpartum depression and anxiety, which are relatively common, and the rare but more severe postpartum psychosis. In addition, other PPDs can include obsessive–compulsive disorder, post-traumatic stress disorder and eating disorders. The aetiology of PPDs is a complex interaction of psychological, social and biological factors, in addition to genetic and environmental factors. The goals of treating postpartum mental illness are reducing maternal symptoms and supporting maternal–child and family functioning. Women and their families should receive psychoeducation about the illness, including evidence-based discussions about the risks and benefits of each treatment option. Developing effective strategies in global settings that allow the delivery of targeted therapies to women with different clinical phenotypes and severities of PPDs is essential

    The Zwicky Transient Facility: System Overview, Performance, and First Results

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    The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg 2 field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF’s public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope

    The Zwicky Transient Facility: Science Objectives

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    The Zwicky Transient Facility (ZTF), a public–private enterprise, is a new time-domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg2 field of view and an 8 second readout time. It is well positioned in the development of time-domain astronomy, offering operations at 10% of the scale and style of the Large Synoptic Survey Telescope (LSST) with a single 1-m class survey telescope. The public surveys will cover the observable northern sky every three nights in g and r filters and the visible Galactic plane every night in g and r. Alerts generated by these surveys are sent in real time to brokers. A consortium of universities that provided funding (“partnership”) are undertaking several boutique surveys. The combination of these surveys producing one million alerts per night allows for exploration of transient and variable astrophysical phenomena brighter than r∌20.5 on timescales of minutes to years. We describe the primary science objectives driving ZTF, including the physics of supernovae and relativistic explosions, multi-messenger astrophysics, supernova cosmology, active galactic nuclei, and tidal disruption events, stellar variability, and solar system objects. © 2019. The Astronomical Society of the Pacific
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