A comparison of direct and electric-current measurements in the Florida Current

Simultaneous measurements of surface velocity obtained in 1967 by means of geomagnetic electrokinetograph and free-instrument techniques aboard two ships in the Florida Current off Ft. Pierce, Florida have been compared . The results show a varying degree of agreement in magnitude across the stream and good agreement in direction. A surprising result is the high seabed conductance

The NASA CYGNSS SmallSat Constellation

The NASA Cyclone Global Navigation Satellite System (CYGNSS) is a constellation of eight microsatellites in low earth orbit at ~525 km altitude and 35 deg inclination. CYGNSS was launched in December 2016 for a planned 2 year mission and 7 of the 8 spacecraft continue to operatue nominally as of May 2023. Each microsatellites carries a bistatic radar receiver to measure reflected GPS signals from the Earth surface. The measurements can be converted to surface wind speed and latent and sensible heat flux over the ocean, and to surface soil moisture and wetland extent over land. Measurements penetrate through all levels of precipitation as well as moderate to heavy vegetation due to the low microwave frequency used by GPS. The number of satellites in the constellation results in sub-daily refresh rates which supports imaging of short time scale weather events such as hurricane rapid intensification, flood inundation dynamics, and sudden soil saturation after major rain events. CYGNSS satellites uses a single string design architecture to reduce the complexity and recurring cost of each unit. Mission redundancy is obtained at the constellation level. Data products are produced by combining measurements from all satellites in such a way that the sampling requirements can be met using only a subset of the satellites. Constellation-level redundancy also permits individual satellites to be switched from their nominal science data taking mode to various engineering test and calibration modes while the overall mission is still able to meet its science requirements

Machine Translation for Accessible Multi-Language Text Analysis

English is the international standard of social research, but scholars are increasingly conscious of their responsibility to meet the need for scholarly insight into communication processes globally. This tension is as true in computational methods as any other area, with revolutionary advances in the tools for English language texts leaving most other languages far behind. In this paper, we aim to leverage those very advances to demonstrate that multi-language analysis is currently accessible to all computational scholars. We show that English-trained measures computed after translation to English have adequate-to-excellent accuracy compared to source-language measures computed on original texts. We show this for three major analytics -- sentiment analysis, topic analysis, and word embeddings -- over 16 languages, including Spanish, Chinese, Hindi, and Arabic. We validate this claim by comparing predictions on original language tweets and their backtranslations: double translations from their source language to English and back to the source language. Overall, our results suggest that Google Translate, a simple and widely accessible tool, is effective in preserving semantic content across languages and methods. Modern machine translation can thus help computational scholars make more inclusive and general claims about human communication.Comment: 5000 words, 6 figure

Complex Biventricular Pacing - A Case Series

AbstractIt is established that cardiac resynchronisation therapy (CRT) reduces mortality and hospitalisation and improves functional class in patients with NYHA class 3-4 heart failure, an ejection fraction of ≤ 35% and a QRS duration of ≥ 120ms. Recent updates in the American guidelines have expanded the demographic of patients in whom CRT may be appropriate. Here we present two cases of complex CRT; one with a conventional indication but occluded central veins and the second with a novel indication for CRT post cardiac transplant

Data Validation of the NASA Time-Resolved Observations of Precipitation Structure and Storm Intensity with a Constellation of Smallsats (TROPICS) Pathfinder Microwave Radiometer

Launched in June 2021, the TROPICS Pathfinder CubeSat has a microwave radiometer payload sensitive to the frequencies for observing precipitation, humidity, temperature, and cloud ice. The observed brightness temperatures must be compared to a data set of ‘known’ quality to validate the measured data across all channels of the microwave radiometer. This research explores validating TROPICS Pathfinder data against reanalysis data to determine the quality of the provisional TROPICS Pathfinder data product, with an eye for the future of comparing against other microwave radiometer measurements. Validation involves comparing Pathfinder data to ERA5 reanalysis data by using the Community Radiative Transfer Model (CRTM) to calculate simulated radiances. The simulated radiances are then compared to the on-orbit Pathfinder data to determine biases, in a method known as single-differencing. The Pathfinder data presented here is at the provisional data maturity level and should be considered preliminary. This effort will be repeated when the TROPICS Pathfinder Level-1 radiances reach the validated data product maturity level late in the summer of 2022. To effectively validate the Pathfinder mission, we have developed a process using MATLAB to read and match the TROPICS Pathfinder data for latitudes between -40° – 40° with desired data for comparison, which is ERA5 in this research. These latitude-longitude data match-ups are then filtered for data points without clouds, using cloud cover data from the GOES-16 satellite. Using data that is cloud-free and overocean ensures that single-differencing comparisons are made using like-data sets and will result in minimal error introduced by the reanalysis and radiative transfer models. After filtering the data, this validation process generates the input files required by CRTM to simulate the model, simulates these observations using the unique Pathfinder CRTM coefficients resulting in the most accurate data, and performs the necessary difference calculations. The end result is an automated process that performs data comparisons for researchers, and we present them as a summary for analysis. The provisional Level-1 radiances show good agreement with combined ERA5 and CRTM simulated radiances, and we expect even better agreement with the upcoming validated Level-1 radiances

The Magnetorotational Instability in a Collisionless Plasma

We consider the linear axisymmetric stability of a differentially rotating collisionless plasma in the presence of a weak magnetic field; we restrict our analysis to wavelengths much larger than the proton Larmor radius. This is the kinetic version of the magnetorotational instability explored extensively as mechanism for magnetic field amplification and angular momentum transport in accretion disks. The kinetic calculation is appropriate for hot accretion flows onto compact objects and for the growth of very weak magnetic fields, where the collisional mean free path is larger than the wavelength of the unstable modes. We show that the kinetic instability criterion is the same as in MHD, namely that the angular velocity decrease outwards. However, nearly every mode has a linear kinetic growth rate that differs from its MHD counterpart. The kinetic growth rates also depend explicitly on beta, i.e., on the ratio of the gas pressure to the pressure of the seed magnetic field. For beta ~ 1 the kinetic growth rates are similar to the MHD growth rates while for beta >> 1 they differ significantly. For beta >> 1, the fastest growing mode has a growth rate of sqrt{3} Omega for a Keplerian disk, larger than its MHD counterpart; there are also many modes whose growth rates are negligible, < beta^{-1/2} Omega << Omega. We provide a detailed physical interpretation of these results and show that gas pressure forces, rather than just magnetic forces, are central to the behavior of the magnetorotational instability in a collisionless plasma. We also discuss the astrophysical implications of our analysis.Comment: Accepted by ApJ; 24 pages (4 figures