Step-response signals recorded at seismic stations in Alaska

This technical report documents the occurrence of a "step-response signal" on seismic stations in Alaska. The unwanted signal occurs both during earthquakes and independent of earthquakes. The cause of the signal is unknown to us, though it has previously been identified in the published seismology literature

Step-response signals recorded during earthquakes in Alaska

We present waveform record sections of 18 earthquakes recorded the Minto Flats fault zone in central Alaska. These include the largest earthquakes to have occurred within the Minto Flats fault zone since the installation of the 13-station FLATS network in September 2015 (Tape and West, 2014). Several seismograms from these earthquakes exhibit a ``step-response signal'' that is a long-period, unwanted signal that does not reflect regional ground motion. We use the term ``anomalously high amplitudes'' to refer to amplitudes within a certain bandpass that exceed the amplitude of earthquake ground motion (within the same bandpass). We attribute anomalously high amplitudes to three possibilities: (1) step-response signal due to local tilt or other effect, (2) step-response signal due to defective sensor, (3) digitizer clipping, (4) high noise (especially before the earthquake). We find widespread occurrences of the step-response signal for earthquakes in the Minto Flats fault zone.This project was supported in part by the National Science Foundation under Grant No. EAR-1352668

Performance review of AK regional seismic network for 2019-2021 with focus on field site telemetry and power

We analyzed Alaska Earthquake Center's field sensor network performance for the time period between October 2019 and September 2021. We report on data completeness and acquisition latencies depending on the site power and data communications types.1. Background 2. Analysis 2.1. Data completeness vs power type 2.2. Data completeness vs internet type 2.3. Data latencies vs power type and internet type 2.5. Data completeness by project 3. Conclusions Appendix

Alaska Earthquake Center Quarterly Technical Report October-December 2021

This series of technical quarterly reports from the Alaska Earthquake Center (AEC) includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, field work, our social media presence, and lists publications and presentations by AEC staff. Multiple AEC staff members contributed to this report. It is issued in the following month after the completion of each quarter Q1: January-March, Q2: April-June, Q3: July-September, and Q4: October-December.1. Introduction 2. Seismicity 3. Field network 4. Data Quality assurance 5. Real-time earthquake detection system 6. Computer systems 6.1 Computer resources 6.2 Waveform storage 6.3 Metadata 6.4 Software development 7. Fieldwork 8. Social media and outreach 8.1. Website 8.2. Twitter 8.3. Facebook (Page) 8.4. Facebook (Group) 9. Publications and presentations 9.1. Publications 9.2. Public Presentations 9.3. Lunch Seminar Talks 10. References Appendix A: Data availability for broadband stations from the AK network. Appendix B: Gaps for broadband stations from the AK network

Status of Muon Collider Research and Development and Future Plans

The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides continued work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (CoM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from a heavy-Z target and proceeding through the phase rotation and decay ($\pi \to \mu \nu_{\mu}$) channel, muon cooling, acceleration, storage in a collider ring and the collider detector. We also present theoretical and experimental R & D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the R & D since the Feasibility Study of Muon Colliders presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A. Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics (Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics, Accelerators and Beam

Access to Reliable Information about Long-Term Prognosis Influences Clinical Opinion on Use of Lifesaving Intervention

Background: Decompressive craniectomy has been traditionally used as a lifesaving rescue treatment in severe traumatic brain injury (TBI). This study assessed whether objective information on long-term prognosis would influence healthcare workers ’ opinion about using decompressive craniectomy as a lifesaving procedure for patients with severe TBI. Method: A two-part structured interview was used to assess the participants ’ opinion to perform decompressive craniectomy for three patients who had very severe TBI. Their opinion was assessed before and after knowing the predicted and observed risks of an unfavourable long-term neurological outcome in various scenarios. Results: Five hundred healthcare workers with a wide variety of clinical backgrounds participated. The participants were significantly more likely to recommend decompressive craniectomy for their patients than for themselves (mean difference in visual analogue scale [VAS] 21.5, 95 % confidence interval 21.3 to 21.6), especially when the next of kin of the patients requested intervention. Patients ’ preferences were more similar to patients who had advance directives. The participants’ preferences to perform the procedure for themselves and their patients both significantly reduced after knowing the predicted risks of unfavourable outcomes, and the changes in attitude were consistent across different specialties, amount of experience in caring for similar patients, religious backgrounds, and positions in the specialty of the participants. Conclusions: Access to objective information on risk of an unfavourable long-term outcome influenced healthcare workers

Expression of cytokine and chemokine mRNA and secretion of tumor necrosis factor-α by gallbladder epithelial cells: Response to bacterial lipopolysaccharides

BACKGROUND: In addition to immune cells, many other cell types are known to produce cytokines. Cultured normal mouse gallbladder epithelial cells, used as a model system for gallbladder epithelium, were examined for their ability to express the mRNA of various cytokines and chemokines in response to bacterial lipopolysaccharide. The synthesis and secretion of the tumor necrosis factor-α (TNF-α) protein by these cells was also measured. RESULTS: Untreated mouse gallbladder cells expressed mRNA for TNF-α, RANTES, and macrophage inflammatory protein-2 (MIP-2). Upon treatment with lipopolysaccharide, these cells now produced mRNA for Interleukin-1β (IL-1β), IL-6, monocyte chemoattractant protein-1 (MCP-1), and showed increased expression of TNF-α and MIP-2 mRNA. Untreated mouse gallbladder cells did not synthesize TNF-α protein; however, they did synthesize and secrete TNF-α upon treatment with lipopolysaccharide. METHODS: Cells were treated with lipopolysaccharides from 3 strains of bacteria. Qualitative and semi-quantitative RT-PCR, using cytokine or chemokine-specific primers, was used to measure mRNA levels of TNFα, IL-1β, IL-6, IL-10, KC, RANTES, MCP-1, and MIP-2. TNF-α protein was measured by immunoassays. CONCLUSION: This research demonstrates that gallbladder epithelial cells in response to lipopolysaccharide exposure can alter their cytokine and chemokine RNA expression pattern and can synthesize and secrete TNFα protein. This suggests a mechanism whereby gallbladder epithelial cells in vivo may mediate gallbladder secretory function, inflammation and diseases in an autocrine/paracrine fashion by producing and secreting cytokines and/or chemokines during sepsis

Individualised prediction of drug resistance and seizure recurrence after medication withdrawal in people with juvenile myoclonic epilepsy: A systematic review and individual participant data meta-analysis

Summary Background A third of people with juvenile myoclonic epilepsy (JME) are drug-resistant. Three-quarters have a seizure relapse when attempting to withdraw anti-seizure medication (ASM) after achieving seizure-freedom. It is currently impossible to predict who is likely to become drug-resistant and safely withdraw treatment. We aimed to identify predictors of drug resistance and seizure recurrence to allow for individualised prediction of treatment outcomes in people with JME. Methods We performed an individual participant data (IPD) meta-analysis based on a systematic search in EMBASE and PubMed – last updated on March 11, 2021 – including prospective and retrospective observational studies reporting on treatment outcomes of people diagnosed with JME and available seizure outcome data after a minimum one-year follow-up. We invited authors to share standardised IPD to identify predictors of drug resistance using multivariable logistic regression. We excluded pseudo-resistant individuals. A subset who attempted to withdraw ASM was included in a multivariable proportional hazards analysis on seizure recurrence after ASM withdrawal. The study was registered at the Open Science Framework (OSF; https://osf.io/b9zjc/). Findings  368) was predicted by an earlier age at the start of withdrawal, shorter seizure-free interval and more currently used ASMs, resulting in an average internal-external cross-validation concordance-statistic of 0·70 (95%CI 0·68–0·73). Interpretation We were able to predict and validate clinically relevant personalised treatment outcomes for people with JME. Individualised predictions are accessible as nomograms and web-based tools. Funding MING fonds

Earthquake Swarms In South America

For this thesis, we performed a manual search for earthquake swarms in South America using the PDE catalog. We chose to perform a manual search because global catalogs are deficient in lower magnitude events and have a potentially low number of events per swarm. With our technique we aim to be insensitive to spatial scales, temporal scales and particularly the number of earthquakes in the potential swarms since seismicity rates vary greatly over the South American continent. However, with a manual search we sacrifice a rigorous approach for one that requires individual interpretation. We identify 35 possible swarms of varying spatial scales and tectonic locations with this search. For most of the events, discussion is limited to several implications about broader tectonic processes due to the lack of additional or higher resolution data (e.g. GPS, InSAR, local seismic catalogs). Several of the events have geodetic data available and for those cases we process and model surface deformation for various slip models and stress changes for earthquake interaction. Two swarms are examined in detail and do not show or are inconclusive for aseismic slip. Seismicity that appears to have been triggered by the Mw=8.5 2001 Peru earthquake is examined and shows that static changes in the Coulomb stress field did not trigger the events, indicating that some dynamic triggering process may have been responsible. We provide evidence that earthquake swarms show a strong degree of interaction with megathrust events by preceding and even marking the limits of large earthquake rupture propagation, showing evidence of stress interaction with megathrust events, and occurring in areas of long standing seismic gaps. We show that swarms commonly occur at the subduction of aseismic ridges and that there may be a potential interaction between swarm locations and trench parallel gravity anomalies. The catalog produced in this thesis appears to agree with previously determined magnitude-frequency scaling laws as well as potentially agreeing with moment-duration scaling laws. Although few volcanic swarms were found, we explore a possible relationship between swarm magnitudes, the frequency of eruption, and temperature of the volcano

Peak Rates and Largest Magnitude Events in Earthquake Swarms From Different Tectonic Settings

We present results of recent studies of earthquake swarms from local data at volcanoes, and teleseismic data from MOR and volcanic regions, focusing on identifying diagnostics. One clear pattern for local volcanic swarms is that peak rates often occur early, whereas the largest magnitude event occurs late. Using a dataset of 20 swarms from the literature, swarm durations, measured from swarm onset to eruption onset, ranged from 12 h to 180 d. Data were normalized to % duration. Peak rates occurred from 1-42% of the total duration (with 2 outliers), whereas the largest M event occurred from 32-99% of duration. Additional evidence from 4 cases suggests that the seismic source size grows systematically, especially for events with similar waveforms (families). This is revealed in plots of size versus time for event families. For comparison, 19 cases of mid-ocean ridge swarms and 67 cases of teleseismic volcanic swarms were analyzed. The MOR data show durations of 1-42 d, with peak rates occurring 1-24% of duration and largest M occurring 1-87% of duration. In 6 cases largest M occurs before or at the same time as peak rate. The teleseismic volcanic data show durations of \u3c1 to 577 d, with peak rates occurring 1-100% of duration and largest M occurring 1-100 % of duration. Thus the patterns for MOR and teleseismic volcanic swarms are similar to each other but differ significantly from that for local volcanic swarms. Further work on volcanic swarms shows the distribution of seismicity before the peak rate differs from after, suggesting two dominant processes. The durations of post-peak portions are roughly proportional to the peak rates. This is similar to the behavior of aftershock sequences and suggests diffusion is a controlling process. The portions of the swarms prior to the peaks behave differently, however. These may represent invasion of hot fluids and opening or reopening of cracks prior to magma intrusion. We infer that the growth in event size reflects activation of a preferred magma pathway. Recognition of such patterns, linked to processes, may help to improve monitoring and reduce risks from eruptions. Comparison is recommended between patterns observed here and those associated with induced seismicity from hydraulic fracturing and deep well injection