A New Mechanism for Early-Time Plasmaspheric Refilling: The Role of Charge Exchange Reactions in the Transport of Energy and Mass Throughout the Ring Current-Plasmasphere System.

Cold H+ produced via charge exchange reactions between ring current ions and exospheric neutral hydrogen constitutes an additional source of cold plasma that further contributes to the plasmasphere and affects the plasma dynamics in the Earth's magnetosphere system; however, its production and associated effects on the plasmasphere dynamics have not been fully assessed and quantified. In this study, we perform numerical simulations mimicking an idealized three-phase geomagnetic storm to investigate the role of heavy ion composition in the ring current (O+ vs. N+) and exospheric neutral hydrogen density in the production of cold H+ via charge exchange reactions. It is found that ring current heavy ions produce more than 50% of the total cold H+ via charge exchange reactions, and energetic N+ is more efficient in producing cold H+ via charge exchange reactions than O+. Furthermore, the density structure of the cold H+ is highly dependent on the mass of the parent ion; that is, cold H+ deriving from charge exchange reactions involving energetic O+ with neutral hydrogen, populates the lower L-shells, while cold H+ deriving from charge exchange reactions involving energetic N+ with neutral hydrogen populates the higher L-shells. In addition, the density of cold H+ produced via charge exchange reactions involving N+ can be peak at values up to one order of magnitude larger than the local plasmaspheric density, suggesting that solely considering the supply of cold plasma from the ionosphere to the plasmasphere can lead to a significant underestimation of plasmasphere density.

Nine Outstanding Questions of Solar Wind Physics.

In situ measurements of the solar wind have been available for almost 60 years, and in that time plasma physics simulation capabilities have commenced and ground-based solar observations have expanded into space-based solar observations. These observations and simulations have yielded an increasingly improved knowledge of fundamental physics and have delivered a remarkable understanding of the solar wind and its complexity. Yet there are longstanding major unsolved questions. Synthesizing inputs from the solar wind research community, nine outstanding questions of solar wind physics are developed and discussed in this commentary. These involve questions about the formation of the solar wind, about the inherent properties of the solar wind (and what the properties say about its formation), and about the evolution of the solar wind. The questions focus on (1) origin locations on the Sun, (2) plasma release, (3) acceleration, (4) heavy-ion abundances and charge states, (5) magnetic structure, (6) Alfven waves, (7) turbulence, (8) distribution-function evolution, and (9) energetic-particle transport. On these nine questions we offer suggestions for future progress, forward looking on what is likely to be accomplished in near future with data from Parker Solar Probe, from Solar Orbiter, from the Daniel K. Inouye Solar Telescope (DKIST), and from Polarimeter to Unify the Corona and Heliosphere (PUNCH). Calls are made for improved measurements, for higher-resolution simulations, and for advances in plasma physics theory.

Effect of Bacillus thuringiensis var. israelensis Sugar Patches on Insecticide Resistant Anopheles gambiae s.l. Adults.

BACKGROUND: Large distribution of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) contributed to a significant decrease in malarial mortality. Unfortunately, large insecticide resistance in malaria vectors occurred and is a threat to the future use of these control approaches. The purpose of this study was to explore a new approach for vector control. Patches containing Bacillus thuringiensis var. israelensis (Bti) solubilized Cry toxins mixed with sugar were developed and tested in the laboratory with pyrethroid-resistant Anopheles gambiae s.l. using tunnel tests. METHODS: Mosquitoes were released at 6:00 p.m. into a large tunnel separated by a bed net, perforated with nine holes, from a smaller chamber with a guinea pig. Nine Bti sugar patches (BSPs) were attached to the bed net between the nine holes. Fourteen hours later (8:00 a.m.), mosquitoes were collected from the tunnel and the guinea pig chamber. Live females were kept in cups and were fed a sugar solution (5%) for 72 h and delayed mortality was followed. The results were reported as passing, blood fed and mortality rates. RESULTS: Mosquito populations that are resistant to the insecticides in the bed net, exhibited high mortality (60%) in the presence of the BSPs. Untreated bed nets with patches in the tunnel test killed 66-95% of the mosquitoes that landed and untreated bed nets were superior to treated bed nets. CONCLUSION: BSPs efficiently kill resistant mosquitoes that land on treated and untreated bed nets and thus could ultimately reduce the number of vector-borne malarial mosquitoes.

The Earth's Magnetosphere: A Systems Science Overview and Assessment.

A systems science examination of the Earth's fully interconnected dynamic magnetosphere is presented. Here the magnetospheric system (a.k.a. the magnetosphere-ionosphere-thermosphere system) is considered to be comprised of 14 interconnected subsystems, where each subsystem is a characteristic particle population: 12 of those particle populations are plasmas and two (the atmosphere and the hydrogen geocorona) are neutrals. For the magnetospheric system, an assessment is made of the applicability of several system descriptors, such as adaptive, nonlinear, dissipative, interdependent, open, irreversible, and complex. The 14 subsystems of the magnetospheric system are cataloged and described, and the various types of magnetospheric waves that couple the behaviors of the subsystems to each other are explained. This yields a roadmap of the connectivity of the magnetospheric system. Various forms of magnetospheric activity beyond geomagnetic activity are reviewed, and four examples of emergent phenomena in the Earth's magnetosphere are presented. Prior systems science investigations of the solar-wind-driven magnetospheric system are discussed: up to the present these investigations have not accounted for the full interconnectedness of the system. This overview and assessment of the Earth's magnetosphere hopes to facilitate (1) future global systems science studies that involve the entire interconnected magnetospheric system with its diverse time and spatial scales and (2) connections of magnetospheric systems science with the broader Earth systems science.

Performance of a malaria microscopy image analysis slide reading device.

BACKGROUND: Viewing Plasmodium in Romanovsky-stained blood has long been considered the gold standard for diagnosis and a cornerstone in management of the disease. This method however, requires a subjective evaluation by trained, experienced diagnosticians and establishing proficiency of diagnosis is fraught with many challenges. Reported here is an evaluation of a diagnostic system (a "device" consisting of a microscope, a scanner, and a computer algorithm) that evaluates scanned images of standard Giemsa-stained slides and reports species and parasitaemia. METHODS: The device was challenged with two independent tests: a 55 slide, expert slide reading test the composition of which has been published by the World Health Organization ("WHO55" test), and a second test in which slides were made from a sample of consenting subjects participating in a malaria incidence survey conducted in Equatorial Guinea (EGMIS test). These subjects' blood was tested by malaria RDT as well as having the blood smear diagnosis unequivocally determined by a worldwide panel of a minimum of six reference microscopists. Only slides with unequivocal microscopic diagnoses were used for the device challenge, n = 119. RESULTS: On the WHO55 test, the device scored a "Level 4" using the WHO published grading scheme. Broken down by more traditional analysis parameters this result was translated to 89% and 70% sensitivity and specificity, respectively. Species were correctly identified in 61% of the slides and the quantification of parasites fell within acceptable range of the validated parasitaemia in 10% of the cases. On the EGMIS test it scored 100% and 94% sensitivity/specificity, with 64% of the species correct and 45% of the parasitaemia within an acceptable range. A pooled analysis of the 174 slides used for both tests resulted in an overall 92% sensitivity and 90% specificity with 61% species and 19% quantifications correct. CONCLUSIONS: In its current manifestation, the device performs at a level comparable to that of many human slide readers. Because its use requires minimal additional equipment and it uses standard stained slides as starting material, its widespread adoption may eliminate the current uncertainty about the quality of microscopic diagnoses worldwide.

Contribution of strong discontinuities to the power spectrum of the solar wind.

Eight and a half years of magnetic field measurements (2(22) samples) from the ACE spacecraft in the solar wind at 1 A.U. are analyzed. Strong (large-rotation-angle) discontinuities in the solar wind are collected and measured. An artificial time series is created that preserves the timing and amplitudes of the discontinuities. The power spectral density of the discontinuity series is calculated and compared with the power spectral density of the solar-wind magnetic field. The strong discontinuities produce a power-law spectrum in the "inertial subrange" with a spectral index near the Kolmogorov -5/3 index. The discontinuity spectrum contains about half of the power of the full solar-wind magnetic field over this "inertial subrange." Warnings are issued about the significant contribution of discontinuities to the spectrum of the solar wind, complicating interpretation of spectral power and spectral indices.