Survey of VLF electric fields in the magnetosphere with the polar orbiting spacecraft, 1964-45a

Very low frequency electric fields in magnetosphere sampled by polar orbiting satellit

Dynamically-Coupled Oscillators -- Cooperative Behavior via Dynamical Interaction --

We propose a theoretical framework to study the cooperative behavior of dynamically coupled oscillators (DCOs) that possess dynamical interactions. Then, to understand synchronization phenomena in networks of interneurons which possess inhibitory interactions, we propose a DCO model with dynamics of interactions that tend to cause 180-degree phase lags. Employing an approach developed here, we demonstrate that although our model displays synchronization at high frequencies, it does not exhibit synchronization at low frequencies because this dynamical interaction does not cause a phase lag sufficiently large to cancel the effect of the inhibition. We interpret the disappearance of synchronization in our model with decreasing frequency as describing the breakdown of synchronization in the interneuron network of the CA1 area below the critical frequency of 20 Hz.Comment: 10 pages, 3 figure

Single electron charging of impurity sites visualized by scanning gate experiments on a quantum point contact

A quantum point contact (QPC) patterned on a two-dimensional electron gas is investigated with a scanning gate setup operated at a temperature of 300 mK. The conductance of the point contact is recorded while the local potential is modified by scanning the tip. Single electron charging of impurities induced by the local potential is observed as a stepwise conductance change of the constriction. By selectively changing the state of some of these impurities, it is possible to observe changes in transmission resonances of the QPC. The location of such impurities is determined, and their density is estimated to be below 50 per \mu m^2, corresponding to less than 1 % of the doping concentration

Symposium on the ILC\u27s State Responsibility Articles: Introduction and Overview

In August 2001, the International Law Commission (ILC) adopted its “Draft Articles on the Responsibility of States for Internationally Wrongful Acts,” bringing to completion one of the Commission\u27s longest running and most controversial studies. On December 12, 2001, the United Nations General Assembly adopted Resolution 56/83, which “commend[ed the articles] to the attention of Governments without prejudice to the question of their future adoption or other appropriate action.” The ILC articles address the fundamental questions: when does a state breach an international obligation and what are the legal consequences? Rather than attempting to define particular “primary” rules of conduct, the articles set forth more general “secondary” rules of responsibility and remedies for breaches of a primary rule. Important issues include: - What is an “internationally wrongful act”? - When does a “breach” of an international obligation occur? - When can a state be held responsible for acts (or omissions) of nonstate actors or of another state? - What circumstances justify otherwise wrongful conduct? - What must a state do to remedy an internationally wrongful act (render compensation, restitution, satisfaction, etc.)? - Which states have standing to complain? - What kinds of countermeasures are permitted and under what circumstances? At the outset, the ILC\u27s first special rapporteur on state responsibility noted, “[I]t would be difficult to find a topic beset with greater confusion and uncertainty.” And throughout the ILC\u27s consideration of the subject, skepticism and controversy abounded, particularly among those trained in the common law, to whom the abstract treatment of “responsibility,” as such, is unfamiliar. Some see the articles as “a bland gruel not likely to upset the most dyspeptic government official,” others as perhaps the ILC\u27s most important product. Whatever one\u27s view of the articles, however, their adoption by the ILC doubtless represents a significant moment in the continuing development of international law. That is the motivation for this symposium

Schmidt hammer and terrestrial laser scanning (TLS) used to detect single‐event displacements on the Pleasant Valley fault (Nevada, USA)

Changes in surface roughness on carbonate fault scarps often reflect varying durations of subaerial weathering. On the Pleasant Valley fault in central Nevada, the documentation of a surface rupture in 1915, a long recurrence interval of faulting, slow weathering rate, and a relatively high (2–3 m) single‐event displacement make the discrimination of the historical and penultimate slip patches unambiguous. Following from a 2018 study, we used a Schmidt hammer and terrestrial laser scanning (TLS) to further test whether these weathering patterns delineate exposed slip patches on a fault scarp. Results show that Schmidt hammer rebound value ranges (termed ΔR – the difference between minimum and maximum R‐values in repeat impacts at a point), increase by ~8–10 points across the historical–penultimate event transition zone in two separate scarp transects. TLS‐derived surface roughness also indicates a clear difference between the most recent and penultimate events. The average single‐event displacement (SED) estimated using the Schmidt hammer and TLS is 2.85 m at two transect sites and is roughly equivalent to the visually estimated 3 m. While this fault is an ideal case where we know some of the slip history, the results demonstrate that these techniques show promise for discriminating slip patches on larger carbonate fault scarps with longer paleoearthquake histories, and could be used alongside 36Cl cosmogenic exposure‐age dating to improve paleoseismic records on normal faults. © 2019 John Wiley & Sons, Ltd.The Schmidt hammer and terrestrial laser scanning (TLS) can detect hardness and mm‐ to cm‐scale surface roughness changes on bedrock fault scarps. Here, we demonstrate that these changes occur between the ‘slip patches’ of a 1915 and pre‐1915 event on the Pleasant Valley fault, yielding single event displacements of ~2‐3 m. These techniques can now be combined to estimate SEDs on larger fault scarps with longer records of paleoearthquakes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154454/1/esp4748.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154454/2/esp4748_am.pd

Groups of Galaxies in the Two Micron All-Sky Redshift Survey

We present the results of applying a percolation algorithm to the initial release of the Two Micron All-Sky Survey Extended Source Catalog, using subsequently measured redshifts for almost all of the galaxies with K < 11.25 mag. This group catalog is based on the first near-IR all-sky flux-limited survey that is complete to |b| = 5 deg. We explore the dependence of the clustering on the length and velocity scales involved. The paper describes a group catalog, complete to a limiting redshift of 10,000 km/s, created by maximizing the number of groups containing 3 or more members. A second catalog is also presented, created by requiring a minimum density contrast of 80 to identify groups. We identify known nearby clusters in the catalogs and contrast the groups identified in the two catalogs. We examine and compare the properties of the determined groups and verify that the results are consistent with the UZC-SSRS2 and northern CfA redshift survey group catalogs. The all-sky nature of the catalog will allow the development of a flow-field model based on the density field inferred from the estimated cluster masses.Comment: Accepted for publication in ApJ (29 pages including 13 figures). A version with high-resolution figures is available at http://www.cfa.harvard.edu/~acrook/preprints

Quaternary Geology and Seismic Hazard of the Sierra Madre and Associated Faults, Western San Gabriel Mountains

This detailed study of a 40-km-long section of the Sierra Madre and associated fault zones in the central transverse Ranges, along the south side of the San Gabriel Mountains, is aimed at providing information for evaluating the seismic hazard that these faults pose to the heavily populated area immediately to the south. Evidence on the location of fault strands and the style and timing of fault movements during the Quaternary was obtained from detailed geologic mapping, aerial-photograph interpretation, alluvial stratigraphy, structural and stratigraphic relations in some 33 trench excavations at critical localities, and subsurface data. We present a time-stratigraphic classification for the Quaternary deposits in the study area, based on soil development, geomorphology, and contact relations among the alluvial units. We distinguish four units, with approximate ages, as follows: unit 4, about 200,000 yr to middle Quaternary; unit 3: about 11,000 to 200,000 yr; unit 2; about 1,000 to 11,000 yr; and unit 1; younger than about 1,000 yr. We use this classification to evaluate on a semi-quantitative basis the evidence for fault activity in the study area and to infer the relative seismicity of different segments of the Sierra Madre fault zone during the Quaternary. Alluvial-fan development (particularly fanhead incision and the ages of alluvial-fan deposits) also gives clues as to relative seismicity. The most active segment of the Sierra Madre fault zone within the study area is the westernmost section, adjacent to the faults that broke during the 1971 San Fernando, Calif., earthquake. The age of activity, as indicated by the occurrence of Holocene faulting, decreases toward the east. Along the Sierra Madre fault, through La Canada, Altadena, Sierra Madre, and Duarte, is abundant evidence of late Pleistocene faulting. Total vertical displacement is more than 600 m, but there is no evidence for Holocene fault movement. These observations suggest that the presently applicable recurrence interval between major earthquakes in the central and eastern sections of the Sierra Madre fault zone is longer than about 5,000 yr. The local magnitude (M_L) of the largest credible earthquake that could occur on the Sierra Madre fault zone in the study area is estimated at 7, on the grounds that the fault zone is probably limited mechanically by subdivision into separate arcuate segments about 15 km long. The Raymond fault, which branches southwestward from the Sierra Madre fault in the eastern part of the study area, shows well-defined evidence of a late Quaternary history of repeated fault movements. Displacements of alluvial strata observed in trench excavations across the fault give evidence of five major seismic events, whose times of occurrence can be estimated from radiometric dating at approximately 36,000, 25,000, 10,000-2,200 (two events), and 2,200-1,500 yr B.P. Further evidence suggests at least three more faulting events in the past 29,000 yr, for which specific dates cannot be determined. Because some additional events probably remain undetected, we infer that an average recurrence interval of about 3,000 yr, with an average vertical displacement of 0.4 m per event, is applicable to the Raymond fault in its present state, as indicated by its history of movement over the past 36,000 yr. This level of activity is distinctly higher than that found for the Sierra Madre fault zone in the central and eastern parts of the study area. If the entire 15-km length of the Raymond fault would rupture in a single event, as seems likely, a maximum credible earthquake of M_L 6 3/4 can reasonably be assumed

Optimizing DNA Extraction Methods for Nanopore Sequencing of Neisseria gonorrhoeae Directly from Urine Samples

Empirical gonorrhea treatment at initial diagnosis reduces onward transmission. However, increasing resistance to multiple antibiotics may necessitate waiting for culture-based diagnostics to select an effective treatment. There is a need for same-day culture-free diagnostics that identify infection and detect antimicrobial resistance. We investigated if Nanopore sequencing can detect sufficient Neisseria gonorrhoeae DNA to reconstruct whole genomes directly from urine samples. We used N. gonorrhoeae-spiked urine samples and samples from gonorrhea infections to determine optimal DNA extraction methods that maximize the amount of N. gonorrhoeae DNA sequenced while minimizing contaminating host DNA. In simulated infections, the Qiagen UCP pathogen mini kit provided the highest ratio of N. gonorrhoeae to human DNA and the most consistent results. Depletion of human DNA with saponin increased N. gonorrhoeae yields in simulated infections but decreased yields in clinical samples. In 10 urine samples from men with symptomatic urethral gonorrhea, ≥92.8% coverage of an N. gonorrhoeae reference genome was achieved in all samples, with ≥93.8% coverage breath at ≥10-fold depth in 7 (70%) samples. In simulated infections, if ≥104 CFU/ml of N. gonorrhoeae was present, sequencing of the large majority of the genome was frequently achieved. N. gonorrhoeae could also be detected from urine in cobas PCR medium tubes and from urethral swabs and in the presence of simulated Chlamydia coinfection. Using Nanopore sequencing of urine samples from men with urethral gonorrhea, sufficient data can be obtained to reconstruct whole genomes in the majority of samples without the need for culture

Reduced incidence of hypertension after heterotopic cardiac transplantation compared with orthotopic cardiac transplantation Evidence that excision of the native heart contributes to post-transplant hypertension

ObjectivesThis study was designed to test the hypothesis that heterotopic heart transplant (HHT) patients have lower blood pressure than orthotopic cardiac transplant (OCT) patients because their native heart is involved in blood pressure homeostasis.BackgroundHypertension occurs more frequently after OCT than after liver or lung transplantation, suggesting that transplantation of the heart itself contributes to post-transplant hypertension.MethodsBlood pressure and related measurements in 233 OCT and 38 HHT patients were studied retrospectively post-transplant.ResultsSystolic blood pressure (SBP) was persistently lower among HHT patients (means 121 vs. 137, 126 vs. 137, 125 vs. 139, and 128 vs. 143 mm Hg at month 3 and years 1, 3, and 5 respectively, p < 0.005). Left ventricular and aortic systolic pressures were also lower (130 vs. 143 mm Hg, p = 0.01 and 129 vs. 142 mm Hg, p = 0.01). Multivariable analysis with age, gender, body mass index, creatinine, steroids, cyclosporine, use of antihypertensive medication, donor left ventricular ejection fraction, donor weight, and type of transplant as covariables showed HHT to be independently associated with a lower SBP at each time point (beta-coefficients −16.2, −12.1, −13.3, and −14.2 mm Hg, p < 0.01). The adjusted hazard ratio for the development of systolic hypertension among HHT compared with OCT patients was 0.59 (95% confidence interval 0.39 to 0.91, p = 0.017).ConclusionsHeterotopic heart transplant patients had lower SBP than OCT patients, consistent with the hypothesis that the native heart continues to contribute to blood pressure homeostasis