Statistically determined dispersion relations of magnetic field fluctuations in the terrestrial foreshock

We obtain dispersion relations of magnetic field fluctuations for two crossings of the terrestrial foreshock by Cluster spacecraft. These crossings cover plasma conditions that differ significantly in their plasma β and in the density of the reflected ion beam, but not in the properties of the encountered ion population, both showing shell-like distribution function. Dispersion relations are reconstructed using two-point instantaneous wave number estimations from pairs of Cluster spacecraft. The accessible range of wave vectors, limited by the available spacecraft separations, extends to ≈2 × 104 km. Results show multiple branches of dispersion relations, associated with different powers of magnetic field fluctuations. We find that sunward propagating fast magnetosonic waves and beam resonant modes are dominant for the high plasma β interval with a dense beam, while the dispersions of the interval with low beam density include Alfvén and fast magnetosonic modes propagating sunward and anti-sunward

Soybean Residual Effects on a Subsequent Maize Crop

Maize (Zea mays 1.) grown after soybean (Glycine max 1. Merr.) consistently performs better than maize that follows itself (second year maize), irrespective of nitrogen fertilization. In previous studies of the soybean-maize rotation, there never has been an evaluation of the potentially different effects of soybean genotypes on following maize. A two-year, soybean maize rotation was initiated in Ames at 1988 with the first year planted to various soybean genotypes, a maize hybrid, and oat (Avena sativa 1.). These were followed in the second year by a single maize hybrid with 0, 80, 160, and 240 kg/ha N fertilization levels. Results are based on three repetitions of this cycle. Averaged over all years and N rates, maize after nodulated soybean and oat yielded 1270 and 1570 kg/ha, 16 and 20% respectively, more than second-year maize. Second-year maize was delayed in silking by 4 days. Though soybean returned 60 to 70 kg/ha of N to the soil in vegetative residue, there seemed to be no net N contribution from soybean to maize because soybean benefited maize less at zero N than did unharvested oat. Soybean evidently returns to the soil less N than is mineralized from soil organic matter during a cropping year. Prior soybean and oat both benefited maize even under the highest nitrogen fertilization rate. BSR 201 soybean benefited maize more than did the other soybean cultivars or oat. Averaged for years and the two highest N rates, BSR 201 benefited maize 680 kg/ha (ca 11 bu/A) more than all the other nodulated soybean genotypes averaged. The BSR 201 effect, however, was not consistent, occurring in two of the three years. Work is continuing using other BSR types

Status of SHAFT 78 with respect to modeling radioactive waste burial in Eleana argillite, including calculations to date

The SHAFT 78 Code (multidimensional, two fluid phases, porous medium) has been used to begin assessment of the consequences of nuclear waste burial in a 1000-acre repository emplaced in argillite. The methodology used can well be applied to other argillaceous rocks as well as to hard rocks in general so long as their in-situ rock permeability can reasonably be assumed to be temperature- and stress-independent. The repository is assumed to contain spent fuel (SF) UO{sub 2} at an initial power loading of 150 kW/acre and located at a depth of 600 m. It was found that with perfect backfill (permeabilty = 1 x 10{sup 7} darcy), a maximum fluid pressure of 770 bars existed in the repository at a time of 55 y after burial. Holding all other input variables constant, the maximum fluid pressure in the repository never exceeded the local lithostatic pressure when the permeability of the backfill material was increased to 1 x 10{sup -1} darcy. The calculated temperature histories are essentially independent of backfill permeability and porosity, indicating that heat transfer is conduction-dominated

Active current sheets and hot flow anomalies in Mercury's bow shock

Hot flow anomalies (HFAs) represent a subset of solar wind discontinuities interacting with collisionless bow shocks. They are typically formed when the normal component of motional (convective) electric field points toward the embedded current sheet on at least one of its sides. The core region of an HFA contains hot and highly deflected ion flows and rather low and turbulent magnetic field. In this paper, we report first observations of HFA-like events at Mercury identified over a course of two planetary years. Using data from the orbital phase of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, we identify a representative ensemble of active current sheets magnetically connected to Mercury's bow shock. We show that some of these events exhibit unambiguous magnetic and particle signatures of HFAs similar to those observed earlier at other planets, and present their key physical characteristics. Our analysis suggests that Mercury's bow shock does not only mediate the flow of supersonic solar wind plasma but also provides conditions for local particle acceleration and heating as predicted by previous numerical simulations. Together with earlier observations of HFA activity at Earth, Venus and Saturn, our results confirm that hot flow anomalies are a common property of planetary bow shocks, and show that the characteristic size of these events is of the order of one planetary radius.Comment: 39 pages, 15 figures, 2 table

Chiropractic treatment of older adults with neck pain with or without headache or dizziness: Analysis of 288 Australian chiropractors' self-reported views

© 2019 The Author(s). Background: Neck pain is a leading cause of individual and societal burden worldwide, affecting an estimated 1 in 5 people aged 70 years and older. The nature and outcomes of chiropractic care for older adults with neck pain, particularly those with co-morbid headaches, remains poorly understood. Therefore, we sought to ascertain: What proportion of Australian chiropractors' caseload comprises older adults with neck pain (with or without headache); How are these conditions treated; What are the reported outcomes? Methods: An online survey examining practitioner and practice characteristics, clinical patient presentations, chiropractic treatment methods and outcomes, and other health service use, was distributed to a random nationally representative sample of 800 Australian chiropractors. Quantitative methods were used to analyze the data. Results: Two hundred eighty-eight chiropractors (response rate = 36%) completed the survey between August and November 2017. Approximately one-third (M 28.5%, SD 14.2) of the chiropractors' patients were older adults (i.e. aged ≥65 years), of which 45.5% (SD 20.6) presented with neck pain and 31.3% (SD 20.3) had co-morbid headache. Chiropractors reported to combine a range of physical and manual therapy treatments, exercises and self-management practices in their care of these patients particularly: manipulation of the thoracic spine (82.0%); activator adjustment of the neck (77.3%); and massage of the neck (76.5%). The average number of visits required to resolve headache symptoms was reported to be highest among those with migraine (M 11.2, SD 8.8). The majority of chiropractors (57.3%) reported a moderate response to treatment in reported dizziness amongst older adults with neck pain. Approximately 82% of older adult patients were estimated to use at least one other health service concurrently to chiropractic care to manage their neck pain. Conclusion: This is the first known study to investigate chiropractic care of older adults living with neck pain. Chiropractors report using well-established conservative techniques to manage neck pain in older adults. Our findings also indicate that this target group of patients may frequently integrate chiropractic care with other health services in order to manage their neck pain. Further research should provide in-depth investigation of older patients' experience and other patient-reported outcomes of chiropractic treatment

Bostonia: The Boston University Alumni Magazine. Volume 20

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Integrating Teaching and Research in Undergraduate Biology Laboratory Education

A course recently designed and implemented at Stanford University applies practical suggestions for creating research-based undergraduate courses that benefit both teaching and research

Effect of substrate thermal resistance on space-domain microchannel

In recent years, Fluorescent Melting Curve Analysis (FMCA) has become an almost ubiquitous feature of commercial quantitative PCR (qPCR) thermal cyclers. Here a micro-fluidic device is presented capable of performing FMCA within a microchannel. The device consists of modular thermally conductive blocks which can sandwich a microfluidic substrate. Opposing ends of the blocks are held at differing temperatures and a linear thermal gradient is generated along the microfluidic channel. Fluorescent measurements taken from a sample as it passes along the micro-fluidic channel permits fluorescent melting curves to be generated. In this study we measure DNA melting temperature from two plasmid fragments. The effects of flow velocity and ramp-rate are investigated, and measured melting curves are compared to those acquired from a commercially available PCR thermocycler