35 research outputs found

    Limits of Earthquake Early Warning Accuracy and Best Alerting Strategy

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    We explore how accurate earthquake early warning (EEW) can be, given our limited ability to forecast expected shaking even if the earthquake source is known. Because of the strong variability of ground motion metrics, such as peak ground acceleration (PGA) and peak ground velocity (PGV), we find that correct alerts (i.e., alerts that accurately estimate the ground motion will be above a predetermined damage threshold) are not expected to be the most common EEW outcome even when the earthquake magnitude and location are accurately determined. Infrequently, ground motion variability results in a user receiving a false alert because the ground motion turned out to be significantly smaller than the system expected. More commonly, users will experience missed alerts when the system does not issue an alert but the user experiences potentially damaging shaking. Despite these inherit limitations, EEW can significantly mitigate earthquake losses for false-alert-tolerant users who choose to receive alerts for expected ground motions much smaller than the level that could cause damage. Although this results in many false alerts (unnecessary alerts for earthquakes that do not produce damaging ground shaking), it minimizes the number of missed alerts and produces overall optimal performance

    The limits of earthquake early warning: Timeliness of ground motion estimates

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    The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a distance from the earthquake, assuming that the earthquake magnitude is not predictable. Earthquake early warning (EEW) systems are in operation or development for many regions around the world, with the goal of providing enough warning of incoming ground shaking to allow people and automated systems to take protective actions to mitigate losses. However, the question of how much warning time is physically possible for specified levels of ground motion has not been addressed. We consider a zero-latency EEW system to determine possible warning times a user could receive in an ideal case. In this case, the only limitation on warning time is the time required for the earthquake to evolve and the time for strong ground motion to arrive at a user’s location. We find that users who wish to be alerted at lower ground motion thresholds will receive more robust warnings with longer average warning times than users who receive warnings for higher ground motion thresholds. EEW systems have the greatest potential benefit for users willing to take action at relatively low ground motion thresholds, whereas users who set relatively high thresholds for taking action are less likely to receive timely and actionable information

    Limits of Earthquake Early Warning Accuracy and Best Alerting Strategy

    Get PDF
    We explore how accurate earthquake early warning (EEW) can be, given our limited ability to forecast expected shaking even if the earthquake source is known. Because of the strong variability of ground motion metrics, such as peak ground acceleration (PGA) and peak ground velocity (PGV), we find that correct alerts (i.e., alerts that accurately estimate the ground motion will be above a predetermined damage threshold) are not expected to be the most common EEW outcome even when the earthquake magnitude and location are accurately determined. Infrequently, ground motion variability results in a user receiving a false alert because the ground motion turned out to be significantly smaller than the system expected. More commonly, users will experience missed alerts when the system does not issue an alert but the user experiences potentially damaging shaking. Despite these inherit limitations, EEW can significantly mitigate earthquake losses for false-alert-tolerant users who choose to receive alerts for expected ground motions much smaller than the level that could cause damage. Although this results in many false alerts (unnecessary alerts for earthquakes that do not produce damaging ground shaking), it minimizes the number of missed alerts and produces overall optimal performance

    Exocrine Pancreatic Insufficiency after Roux-en-Y gastric bypass.

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    BACKGROUND Gastric resection, short bowel syndrome, and diabetes mellitus are risk factors for development of exocrine pancreatic insufficiency (EPI). Reasons are multifactorial and not completely elucidated. OBJECTIVES To determine the prevalence of EPI after distal (dRYGB) and proximal Roux-en-Y gastric bypass (pRYGB) and to assess the influence of respective limb lengths. SETTING University hospital, Switzerland. METHODS The study comprised 188 consecutive patients who underwent primary dRYGB (common channel200 and<500 μg/g stool and positive dechallenge-rechallenge test with pancreatic enzyme replacement therapy. RESULTS Mean follow-up was 52.2 months (range 24-120). Seventy-nine patients (42%) underwent dRYGB, and 109 (58%) underwent pRYGB. Of those, 59 (31%) patients were diagnosed with EPI after a mean 12.5±16.3 months. There was a significant difference between dRYGB and pRYGB groups in initial body mass index (dRYGB 47.1±8.1 kg/m(2) versus pRYGB 42.7±6.1 kg/m(2); P<.01), patients in Obesity Surgery Mortality Risk Score group C (13% versus 3%; P = .02), and prevalence of EPI (48% versus 19%; P<.01). Neither overall small bowel length nor absolute or relative limb lengths were influencing factors on EPI after dRYGB. CONCLUSION Prevalence of EPI after dRYGB (48%) and pRYGB (19%) is of clinical importance. There was no significant difference in absolute or relative limb lengths between EPI and non-EPI groups after dRYGB

    Expression and purification of mammalian calreticulin in Pichia pastoris.

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    Calreticulin is a 46-kDa Ca(2+)-binding chaperone of the endoplasmic reticulum membranes. The protein binds Ca(2+) with high capacity, affects intracellular Ca(2+) homeostasis, and functions as a lectin-like chaperone. In this study, we describe expression and purification procedures for the isolation of recombinant rabbit calreticulin. The calreticulin was expressed in Pichia pastoris and purified to homogeneity by DEAE-Sepharose and Resource Q FPLC chromatography. The protein was not retained in the endoplasmic reticulum of Pichia pastoris but instead it was secreted into the external media. The purification procedures reported here for recombinant calreticulin yield homogeneous preparations of the protein by SDS-PAGE and mass spectroscopy analysis. Purified calreticulin was identified by its NH(2)-terminal amino acid sequences, by its Ca(2+) binding, and by its reactivity with anti-calreticulin antibodies. The protein contained one disulfide bond between (88)Cys and (120)Cys. CD spectral analysis and Ca(2+)-binding properties of the recombinant protein indicated that it was correctly folded

    Interaction between a Ca2+-binding protein calreticulin and perforin, a component of the cytotoxic T-cell granules

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    Calreticulin is a component of cytotoxic T-lymphocyte and NK lymphocyte granules. We report here that granule-associated calreticulin terminates with the KDEL endoplasmic reticulum retrieval amino acid sequence and somehow escapes the KDEL retrieval system. In perforin knock-out mice calreticulin is still targeted into the granules. Thus, calreticulin will traffic without perforin to cytotoxic granules. In the granules, calreticulin and perforin are associated as documented by (i) copurification of calreticulin with perforin but not with granzymes and (ii) immunoprecipitation of a calreticulin-perforin complex using specific antibodies. By using calreticulin affinity chromatography and protein ligand blotting we show that perforin binds to calreticulin in the absence of Ca2+ and the two proteins dissociate upon exposure to 0.1 mM or higher Ca2+ concentration. Perforin interacts strongly with the P-domain of calreticulin (the domain which has high Ca2+-binding affinity and chaperone function) as revealed by direct protein-protein interaction, ligand blotting, and the yeast two-hybrid techniques. Our results suggest that calreticulin may act as Ca2+-regulated chaperone for perforin. This action will serve to protect the CTL during biogenesis of granules and may also serve to regulate perforin lytic action after release

    Teacher's Stress in Relation to Teaching Efficacy at the College of Hotel and Restaurant Management in A University

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    Since the dawn of early 1980's, up to present, there has been a growing interest among highly developed countries about the increase and causes of stress among the teachers both at work and in their life. The never-ending change in the educational landscape had a significant effect on this rate of change, starting with the advent of the K-12 program, the Outcome Based Education Curriculum and the Outcome Based Teaching and Learning, not to mention the publish or perish policy implemented by the universities to cope with the looming typology under the Commission on Higher Education regulations. This study made use of the survey method of research. It was found out that majority of the respondents have moderately noticeable level of stress in time management and work- related stressors. Majority of the teachers are efficient enough in engaging students in their respective classes, coming up with good instructional strategies and effective classroom management. A stress management program was proposed to provide information on the causes and consequences of excess stress
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