2,565 research outputs found
Adjoint analysis of the source and path sensitivities of basin-guided waves
Simulations of earthquake rupture on the southern San Andreas Fault (SAF) reveal large amplifications in the San Gabriel and Los Angeles Basins (SGB and LAB) apparently associated with long-range path effects. Geometrically similar excitation patterns can be recognized repeatedly in different SAF simulations (e.g. Love wave-like energy with predominant period around 4 s, channelled southwestwardly from the SGB into LAB), yet the amplitudes with which these distinctive wavefield patterns are excited change, depending upon source details (slip distribution, direction and velocity of rupture). We describe a method for rapid calculation of the sensitivity of such predicted wavefield features to perturbations of the source kinematics, using a time-reversed (adjoint) wavefield simulation. The calculations are analogous to those done in adjoint tomography, and the same time-reversed calculation also yields path-sensitivity kernels that give further insight into the excitation mechanism. For rupture on the southernmost 300 km of SAF, LAB excitation is greatest for slip concentrated between the northern Coachella Valley and the transverse ranges, propagating to the NE and with rupture velocities between 3250 and 3500 m s-1 along that fault segment; that is, within or slightly above the velocity range (between Rayleigh and S velocities) that is energetically precluded in the limit of a sharp rupture front, highlighting the potential value of imposing physical constraints (such as from spontaneous rupture models) on source parametrizations. LAB excitation is weak for rupture to the SW and for ruptures in either direction located north of the transverse transverse ranges, whereas Ventura Basin (VTB) is preferentially excited by NE ruptures situated north of the transverse ranges. Path kernels show that LAB excitation is mediated by surface waves deflected by the velocity contrast along the southern margin of the transverse ranges, having most of their energy in basement rock until they impinge on the eastern edge of SGB, through which they are then funnelled into LAB. VTB amplification is enhanced by a similar waveguide effec
Defensin Susceptibility and Colonization in the Mouse Model of AJ100, a Polymyxin B-Resistant, Brucella abortus RB51 Isolate
Intracellular pathogens selected for increased susceptibility to polycations are commonly attenuated, yet the effect of decreased susceptibility to polycations on pathogenicity has not been researched. The polymyxin-resistant mutant Brucella abortus AJ100 was characterized by comparing its susceptibility to the polycationic antibiotic polymyxin B, defensins, and lactoferricin, and its colonization and clearance in the mouse model to the parent strain RB51. MIC (minimum inhibitory concentration) values determined by Etest for AJ100 and RB51 were 1.5 and 0.25 μg/ml, respectively. Though AJ100 is less susceptible to polymyxin B than RB51, it was more susceptible than its parent strain to the cationic defensins melittin, magainin 2, and cecropin P1. In the mouse model, initial colonization of the spleen was lower for AJ100 than RB51, and the rate of clearance from the spleen was faster for AJ100 than RB51. However, initial colonization and clearance rates of AJ100 from the liver were indistinguishable from those of RB51. This study suggests that the susceptibility profile of Brucella to polycationic defensins rather than polymyxin B may be indicative of differential survival in the spleen and liver in the mouse and is indicative of spleen and liver residential macrophages’ differing ability to inactivate Brucella
Spontaneous Epiglottic Hematoma Secondary to Supratherapeutic Anticoagulation
Hemorrhage into the soft tissues of the airway represents a potentially life-threatening complication of long-term anticoagulation. We report the case of a chronically anticoagulated 37-year-old male who developed a spontaneous hematoma of the epiglottis secondary to a supra-therapeutic INR. Epiglottic hematoma should be considered in the differential of any anticoagulated patient presenting with upper airway compromise. The airway should be secured in a controlled fashion, and the coagulopathy should be rapidly corrected
Bilateral Vallecular Cysts as a Cause of Dysphagia: Case Report and Literature Review
Cysts of the vallecula are rare, accounting for 10.5% to 20.1% of all laryngeal cysts. Vallecular cysts may present with diverse symptoms affecting the voice, airway, and swallowing. We describe the evaluation and treatment of a 70-year-old woman who presented with dysphagia caused by large bilateral vallecular cysts
Hunter S. Thompson and gonzo journalism: A research guide.
Purpose – The purpose of this paper is to identify and annotate resources related to Hunter S. Thompson and Gonzo Journalism. Design/methodology/approach – Numerous searches are performed in online library catalogs, online databases, and web search engines to identify monographs, journal articles, multimedia titles, and web sites relevant to the topic. Resources located in the searches are then reviewed and annotated by the author and selected for inclusion in the paper based on their relative quality. Findings – A great deal of popular work has been devoted to Thompson and Gonzo Journalism, but also a surprising amount of scholarly analysis. Most primary source material is now available in monographic form, and critical literature is fairly evenly distributed between journal articles and monographs. Search results for Thompson and Gonzo Journalism are often complicated by a number of factors, but these can be compensated for by using search limiters. Research limitations/implications – Because of the sheer volume of work, scholarly and popular, devoted to Thompson and Gonzo Journalism, it is not possible to provide a comprehensive evaluation of all of the materials on the topic. While every attempt is made to be inclusive, the goal of the guide was to include the best sources on the topic, and some resources are reviewed but not included because of quality issues. A number of un-annotated bibliographies are referenced that would be helpful in directing readers to additional resources not included here. Originality/value – Although there are bibliographies of Thompson\u27s work, none are annotated or prepared with academic researchers in mind. In addition, none of the bibliographies located in the course of researching the paper attempted to identify academic journal literature related to Thompson or Gonzo Journalism
BEHAVIOR OF SANDHILL CRANES HARNESSED WITH DIFFERENT SATELLITE TRANSMITTERS
The effectiveness of various attachment methods and designs of platform transmitting terminals (PIT\u27s) was tested on captive sandhill cranes (Grus canadensis) at the Patuxent Wildlife Research Center, Laurel, Maryland, during 1989-91. Combinations of attachment and transmitter designs included neoprene cord harness with batteries separate from the transmitter (2 harness designs), Teflon ribbon harness with batteries incorporated into the transmitter package (4 transmitter models), and a package attached directly to the bird with epoxy glue only. Physical effects seen on cranes wearing PTT\u27s ranged from skin lacerations (caused by rubbing of harness material) to no observed effects (other than feather wear). The most successful harness material and design utilized a Teflon ribbon harness with the 4 ribbon ends from the transmitter forming a neck loop and a body loop joined at the sternum. Time spent by sandhill cranes performing most activities did not change after transmitter attachment using this harness method
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Pleural Fluid Mesothelin as an Adjunct to the Diagnosis of Pleural Malignant Mesothelioma
Rationale:. The diagnosis of pleural malignant mesothelioma (MM) by effusion cytology may be difficult and is currently controversial. Effusion mesothelin levels are increased in patients with MM but the clinical role of this test is uncertain. Objectives:. To determine the clinical value of measuring mesothelin levels in pleural effusion supernatant to aid diagnosis of MM. Methods and Measurements. Pleural effusion samples were collected prospectively from 1331 consecutive patients. Mesothelin levels were determined by commercial ELISA in effusions and their relationship to concurrent pathology reporting and final clinical diagnosis was determined. Results:. 2156 pleural effusion samples from 1331 individuals were analysed. The final clinical diagnosis was 183 MM, 436 non-MM malignancy, and 712 nonmalignant effusions. Effusion mesothelin had a sensitivity of 67% for MM at 95% specificity. Mesothelin was elevated in over 47% of MM cases in effusions obtained before definitive diagnosis of MM was established. In the setting of inconclusive effusion cytology, effusion mesothelin had a positive predictive value of 79% for MM and 94% for malignancy. Conclusions:. A mesothelin-positive pleural effusion, irrespective of the identification of malignant cells, indicates the likely presence of malignancy and adds weight to the clinical rationale for further investigation to establish a malignant diagnosis
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The evolution of mapping habitat for northern spotted owls (Strix occidentalis caurina): A comparison of photo-interpreted, Landsat-based, and lidar-based habitat maps
Wildlife habitat mapping has evolved at a rapid pace over the last few decades. Beginning with simple, often subjective,
hand-drawn maps, habitat mapping now involves complex species distribution models (SDMs) using
mapped predictor variables derived from remotely sensed data. For species that inhabit large geographic areas,
remote sensing technology is often essential for producing range wide maps. Habitat monitoring for northern
spotted owls (Strix occidentalis caurina), whose geographic covers about 23 million ha, is based on SDMs that
use Landsat Thematic Mapper imagery to create forest vegetation data layers using gradient nearest neighbor
(GNN) methods. Vegetation data layers derived from GNN are modeled relationships between forest inventory
plot data, climate and topographic data, and the spectral signatures acquired by the satellite. When used as predictor
variables for SDMs, there is some transference of the GNN modeling error to the final habitat map.
Recent increases in the use of light detection and ranging (lidar) data, coupled with the need to produce spatially
accurate and detailed forest vegetation maps have spurred interest in its use for SDMs and habitat mapping. Instead
of modeling predictor variables from remotely sensed spectral data, lidar provides direct measurements of
vegetation height for use in SDMs. We expect a SDM habitat map produced from directly measured predictor variables
to be more accurate than one produced from modeled predictors.
We used maximum entropy (Maxent) SDM modeling software to compare predictive performance and estimates
of habitat area between Landsat-based and lidar-based northern spotted owl SDMs and habitat maps.
We explored the differences and similarities between these maps, and to a pre-existing aerial photo-interpreted
habitat map produced by local wildlife biologists. The lidar-based map had the highest predictive
performance based on 10 bootstrapped replicate models (AUC = 0.809 ± 0.011), but the performance of
the Landsat-based map was within acceptable limits (AUC = 0.717 ± 0.021). As is common with photo-interpreted
maps, there was no accuracy assessment available for comparison. The photo-interpreted map produced
the highest and lowest estimates of habitat area, depending on which habitat classes were included
(nesting, roosting, and foraging habitat = 9962 ha, nesting habitat only = 6036 ha). The Landsat-based map
produced an estimate of habitat area that was within this range (95% CI: 6679–9592 ha), while the lidar-based
map produced an area estimate similar to what was interpreted by local wildlife biologists as nesting (i.e., high
quality) habitat using aerial imagery (95% CI: 5453–7216). Confidence intervals of habitat area estimates from
the SDMs based on Landsat and lidar overlapped.
We concluded that both Landsat- and lidar-based SDMs produced reasonable maps and area estimates for northern
spotted owl habitat within the study area. The lidar-based map was more precise and spatially similar to
what local wildlife biologists considered spotted owl nesting habitat. The Landsat-based map provided a less precise
spatial representation of habitat within the relatively small geographic confines of the study area, but habitat
area estimates were similar to both the photo-interpreted and lidar-based maps.
Photo-interpreted maps are time consuming to produce, subjective in nature, and difficult to replicate. SDMs provide
a framework for efficiently producing habitat maps that can be replicated as habitat conditions change over
time, provided that comparable remotely sensed data are available. When the SDM uses predictor variables extracted
from lidar data, it can produce a habitat map that is both accurate and useful at large and small spatial scales. In comparison, SDMs using Landsat-based data are more appropriate for large scale analyses of amounts
and general spatial patterns of habitat at regional scales.Keywords: GNN,
Landsat TM,
Northern spotted owl,
Maxent,
Species distribution modeling,
Lidar,
Habitat suitabilit
Response Function of the Fractional Quantized Hall State on a Sphere I: Fermion Chern-Simons Theory
Using a well known singular gauge transformation, certain fractional
quantized Hall states can be modeled as integer quantized Hall states of
transformed fermions interacting with a Chern-Simons field. In previous work we
have calculated the electromagnetic response function of these states at
arbitrary frequency and wavevector by using the Random Phase Approximation
(RPA) in combination with a Landau Fermi Liquid approach. We now adopt these
calculations to a spherical geometry in order to facilitate comparison with
exact diagonalizations performed on finite size systems.Comment: 39 pages (REVTeX 3.0). Postscript file for this paper are available
on the World Wide Web at http://cmtw.harvard.edu/~simon/ ; Preprint number
HU-CMT-94S0
Convergence towards a European strategic culture? A constructivist framework for explaining changing norms.
The article contributes to the debate about the emergence of a European strategic culture to underpin a European Security and Defence Policy. Noting both conceptual and empirical weaknesses in the literature, the article disaggregates the concept of strategic culture and focuses on four types of norms concerning the means and ends for the use of force. The study argues that national strategic cultures are less resistant to change than commonly thought and that they have been subject to three types of learning pressures since 1989: changing threat perceptions, institutional socialization, and mediatized crisis learning. The combined effect of these mechanisms would be a process of convergence with regard to strategic norms prevalent in current EU countries. If the outlined hypotheses can be substantiated by further research the implications for ESDP are positive, especially if the EU acts cautiously in those cases which involve norms that are not yet sufficiently shared across countries
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