466 research outputs found

    Spatial distribution and energy release of nonvolcanic tremor at Parkfield, California

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    Nonvolcanic tremors (NVTs) are observed in transition zones between freely slipping andlocked sections of faults and normally occur below the seismogenic zone. Based on NVT recordings in theParkfield region of the San Andreas Fault, we provide a novel approach to assess the energy release of theseevents and assign magnitudes (Me) that are compatible with size estimates of small earthquakes in the sameregion. To assess the energy magnitude of a detected tremor, we refine the estimate of its duration andperform a spectral analysis that accounts for local attenuation. For the 218 NVTs that we were able to process,we resolveMevalues in the range of 0.67 to 0.84. For events, which we could not process using the spectralanalysis technique, we propose a statistical model to estimateMevalues using observable characteristics,such as peak amplitude, spectral velocity at the source corner frequency, and duration. We furthermoreprovide seismic moment and moment magnitude estimates and calculate stress drops in a range of 3–10 kPa.As a result of our spectral analyses, wefind strong indications regarding the ongoing debate aboutpotential NVT location hypotheses: the Parkfield NVTs have a higher probability to be located in the proposedthree-dimensional cloud-like cluster than in any other suggested location distributi

    Berry's Phases of Ground States of Interacting Spin-One Bosons: Chains of Monopoles and Monosegments

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    We study Berry's connection potentials of many-body ground states of spin-one bosons with antiferromagnetic interactions in adiabatically varying magnetic fields. We find that Berry's connection potentials are generally determined by, instead of usual singular monopoles, linearly positioned monosegments each of which carries one unit of topological charge; in the absence of a magnetic field gradient this distribution of monosegments becomes a linear chain of monopoles. Consequently, Berry's phases consist of a series of step functions of magnetic fields; a magnetic field gradient causes rounding of these step-functions. We also calculate Berry's connection fields, profiles of monosegments and show that the total topological charge is conserved in a parameter space

    The frequency-size scaling of non-volcanic tremors beneath the San Andreas Fault at Parkfield: Possible implications for seismic energy release

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    © 2019 Elsevier B.V. We analyse the frequency-size-distribution of non-volcanic tremors observed along the Parkfield section of the San Andreas Fault. We suggest that these non-volcanic tremors follow a power-law scaling typical of scale-invariant, stick slip tectonic earthquakes, but with an unusually high scaling exponent of more than 2.0 and a systematic depth-dependency. While each individual non-volcanic tremor releases only a minuscule amount of energy and slip, this is more than compensated by their sheer numbers. Consequently, the integrated contribution of this largely ‘invisible’ seismicity (non-volcanic tremors and nano-earthquakes) is non-negligible and could potentially account in selected patches along the San Andreas fault for up to 100% of the plate motion

    Combining controlled-source seismology and receiver function information to derive 3-D Moho topography for Italy

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    The accurate definition of 3-D crustal structures and, in primis, the Moho depth, are the most important requirement for seismological, geophysical and geodynamic modelling in complex tectonic regions. In such areas, like the Mediterranean region, various active and passive seismic experiments are performed, locally reveal information on Moho depth, average and gradient crustal Vp velocity and average Vp/Vs velocity ratios. Until now, the most reliable information on crustal structures stems from controlled-source seismology experiments. In most parts of the Alpine region, a relatively large number of controlled-source seismology information are available though the overall coverage in the central Mediterranean area is still sparse due to high costs of such experiments. Thus, results from other seismic methodologies, such as local earthquake tomography, receiver functions and ambient noise tomography can be used to complement the controlled-source seismology information to increase coverage and thus the quality of 3-D crustal models. In this paper, we introduce a methodology to directly combine controlled-source seismology and receiver functions information relying on the strengths of each method and in relation to quantitative uncertainty estimates for all data to derive a well resolved Moho map for Italy. To obtain a homogeneous elaboration of controlled-source seismology and receiver functions results, we introduce a new classification/weighting scheme based on uncertainty assessment for receiver functions data. In order to tune the receiver functions information quality, we compare local receiver functions Moho depths and uncertainties with a recently derived well-resolved local earthquake tomography-derived Moho map and with controlled-source seismology information. We find an excellent correlation in the Moho information obtained by these three methodologies in Italy. In the final step, we interpolate the controlled-source seismology and receiver functions information to derive the map of Moho topography in Italy and surrounding regions. Our results show high-frequency undulation in the Moho topography of three different Moho interfaces, the European, the Adriatic-Ionian, and the Liguria-Corsica-Sardinia-Tyrrhenia, reflecting the complexity of geodynamical evolutio

    Everolimus dosing recommendations for tuberous sclerosis complex–associated refractory seizures

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    ObjectiveThe present analysis examined the exposure-response relationship by means of the predose everolimus concentration (C-min) and the seizure response in patients with tuberous sclerosis complex-associated seizures in the EXIST-3 study. Recommendations have been made for the target C-min range of everolimus for therapeutic drug monitoring (TDM) and the doses necessary to achieve this target C-min

    Short-term stability in refractive status despite large fluctuations in glucose levels in diabetes mellitus type 1 and 2

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    Purpose: This work investigates how short-term changes in blood glucose concentration affect the refractive components of the diabetic eye in patients with long-term Type 1 and Type 2 diabetes. Methods: Blood glucose concentration, refractive error components (mean spherical equivalent MSE, J0, J45), central corneal thickness (CCT), anterior chamber depth (ACD), crystalline lens thickness (LT), axial length (AL) and ocular aberrations were monitored at two-hourly intervals over a 12-hour period in: 20 T1DM patients (mean age ± SD) 38±14 years, baseline HbA1c 8.6±1.9%; 21 T2DM patients (mean age ± SD) 56±11 years, HbA1c 7.5±1.8%; and in 20 control subjects (mean age ± SD) 49±23 years, HbA1c 5.5±0.5%. The refractive and biometric results were compared with the corresponding changes in blood glucose concentration. Results: Blood glucose concentration at different times was found to vary significantly within (p0.05). Minor changes of marginal statistical or optical significance were observed in some biometric parameters. Similarly there were some marginally significant differences between the baseline biometric parameters of well-controlled and poorly-controlled diabetic subjects. Conclusion: This work suggests that normal, short-term fluctuations (of up to about 6 mM/l on a timescale of a few hours) in the blood glucose levels of diabetics are not usually associated with acute changes in refractive error or ocular wavefront aberrations. It is therefore possible that factors other than refractive error fluctuations are sometimes responsible for the transient visual problems often reported by diabetic patients

    Inequalities' Impacts: State of the Art Review

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    By way of introduction This report provides the fi rm foundation for anchoring the research that will be performed by the GINI project. It subsequently considers the fi elds covered by each of the main work packages: ● inequalities of income, wealth and education, ● social impacts, ● political and cultural impacts, and ● policy effects on and of inequality. Though extensive this review does not pretend to be exhaustive. The review may be “light” in some respects and can be expanded when the analysis evolves. In each of the four fi elds a signifi cant number of discussion papers will be produced, in total well over 100. These will add to the state of the art while also covering new round and generating results that will be incorporated in the Analysis Reports to be prepared for the work packages. In that sense, the current review provides the starting point. At the same time, the existing body of knowledge is broader or deeper depending on the particular fi eld and its tradition of research. The very motivation of GINI’s focused study of the impacts of inequalities is that a systematic study is lacking and relatively little is known about those impacts. This also holds for the complex collection of, the effects that inequality can have on policy making and the contributions that policies can make to mitigating inequalities but also to enhancing them. By contrast, analyses of inequality itself are many, not least because there is a wide array of inequalities; inequalities have become more easily studied comparatively and much of that analysis has a signifi cant descriptive fl avour that includes an extensive discussion of measurement issues. @GINI hopes to go beyond that and cover the impacts of inequalities at the same time

    MicroRNA response to hypoxic stress in soft tissue sarcoma cells: MicroRNA mediated regulation of HIF3α

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    Background: Hypoxia is often encountered in solid tumors and known to contribute to aggressive tumor behavior, radiation- and chemotherapy resistance resulting in a poor prognosis for the cancer patient. MicroRNAs (miRNAs) play a role in the regulation of the tumor cell response to hypoxia, however, not much is known about the involvement of miRNAs in hypoxic signalling pathways in soft tissue sarcomas (STS).Method: A panel of twelve STS cell lines was exposed to atmospheric oxygen concentrations (normoxia) or 1% oxygen (hypoxia) for up to 48 h. Hypoxic conditions were verified and miRNA expression profiles were assessed by LNA™ oligonucleotide microarrays and RT-PCR after 24 h. The expression of target genes regulated by hypoxia responsive miRNAs is examined by end-point PCR and validated by luciferase reporter constructs.Results: Exposure of STS cell lines to hypoxic conditions gave rise to upregulation of Hypoxia Inducible Factor (HIF) 1α protein levels and increased mRNA expression of HIF1 target genes CA9 and VEGFA. Deregulation of miRNA expression after 24 h of hypoxia was observed. The most differentially expressed miRNAs (p < 0.001) in response to hypoxia were miR-185-3p, miR-485-5p, miR-216a-5p (upregulated) and miR-625-5p (downregulated). The well-known hypoxia responsive miR-210-3p could not be reliably detected by the microarray platform most likely for technical reasons, however, its upregulation upon hypoxic stress was apparent by qPCR. Target prediction algorithms identified 11 potential binding sites for miR-485-5p and a single putative miR-210-3p binding site in the 3'UTR of HIF3α, the least studied member of the HIF family. We showed that HIF3α transcripts, expressing a 3'UTR containing the miR-485-5p and miR-210-3p target sites, are expressed in all sarcoma cell lines and upregulated upon hypoxia. Additionally, luciferase reporter constructs containing the 3'UTR of HIF3α were used to demonstrate regulation of HIF3α by miR-210-3p and miR-485-5p.Conclusion: Here we provide evidence for the miRNA mediated regulation of HIF3α by hypoxia responsive miRNAs in STS, which may help to tightly regulate and fine-tune the hypoxic response. This provides a better insight into the mechanisms underlying the hypoxic response in STS and may ultimately yield information on novel prognostic and predictive markers or targets for treatment
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