Electron Vorticity Indicative of the Electron Diffusion Region of Magnetic Reconnection.

While vorticity defined as the curl of the velocity has been broadly used in fluid and plasma physics, this quantity has been underutilized in space physics due to low time resolution observations. We report Magnetospheric Multiscale (MMS) observations of enhanced electron vorticity in the vicinity of the electron diffusion region of magnetic reconnection. On 11 July 2017 MMS traversed the magnetotail current sheet, observing tailward-to-earthward outflow reversal, current-carrying electron jets in the direction along the electron meandering motion or out-of-plane direction, agyrotropic electron distribution functions, and dissipative signatures. At the edge of the electron jets, the electron vorticity increased with magnitudes greater than the electron gyrofrequency. The out-of-plane velocity shear along distance from the current sheet leads to the enhanced vorticity. This, in turn, contributes to the magnetic field perturbations observed by MMS. These observations indicate that electron vorticity can act as a proxy for delineating the electron diffusion region of magnetic reconnection.

New Closures for More Precise Modeling of Landau Damping in the Fluid Framework.

Incorporation of kinetic effects such as Landau damping into a fluid framework was pioneered by Hammett and Perkins, by obtaining closures of the fluid hierarchy, where the gyrotropic heat flux fluctuations or the deviation of the fourth-order gyrotropic fluid moment are expressed through lower-order fluid moments. To obtain a closure of a fluid model expanded around a bi-Maxwellian distribution function, the usual plasma dispersion function Z(ζ) that appears in kinetic theory or the associated plasma response function R(ζ)=1+ζZ(ζ) has to be approximated with a suitable Padé approximant in such a way that the closure is valid for all ζ values. Such closures are rare, and the original closures of Hammett and Perkins are often employed. Here we present a complete mapping of all plausible Landau fluid closures that can be constructed at the level of fourth-order moments in the gyrotropic limit and we identify the most precise closures. Furthermore, by considering 1D closures at higher-order moments, we show that it is possible to reproduce linear Landau damping in the fluid framework to any desired precision, thus showing convergence of the fluid and collisionless kinetic descriptions.

Coalescence of Macroscopic Flux Ropes at the Subsolar Magnetopause: Magnetospheric Multiscale Observations.

We report unambiguous in situ observation of the coalescence of macroscopic flux ropes by the magnetospheric multiscale (MMS) mission. Two coalescing flux ropes with sizes of ∼1 R_{E} were identified at the subsolar magnetopause by the occurrence of an asymmetric quadrupolar signature in the normal component of the magnetic field measured by the MMS spacecraft. An electron diffusion region (EDR) with a width of four local electron inertial lengths was embedded within the merging current sheet. The EDR was characterized by an intense parallel electric field, significant energy dissipation, and suprathermal electrons. Although the electrons were organized by a large guide field, the small observed electron pressure nongyrotropy may be sufficient to support a significant fraction of the parallel electric field within the EDR. Since the flux ropes are observed in the exhaust region, we suggest that secondary EDRs are formed further downstream of the primary reconnection line between the magnetosheath and magnetospheric fields.

Kinetic scale turbulence and dissipation in the solar wind: key observational results and future outlook.

Turbulence is ubiquitous in the solar wind. Turbulence causes kinetic and magnetic energy to cascade to small scales where they are eventually dissipated, adding heat to the plasma. The details of how this occurs are not well understood. This article reviews the evidence for turbulent dissipation and examines various diagnostics for identifying solar wind regions where dissipation is occurring. We also discuss how future missions will further enhance our understanding of the importance of turbulence to solar wind dynamics.

Bidirectional energy cascades and the origin of kinetic Alfvénic and whistler turbulence in the solar wind.

The observed steep kinetic scale turbulence spectrum in the solar wind raises the question of how that turbulence originates. Observations of keV energetic electrons during solar quiet time suggest them as a possible source of free energy to drive kinetic turbulence. Using particle-in-cell simulations, we explore how the free energy released by an electron two-stream instability drives Weibel-like electromagnetic waves that excite wave-wave interactions. Consequently, both kinetic Alfvénic and whistler turbulence are excited that evolve through inverse and forward magnetic energy cascades.

Detection of small-scale structures in the dissipation regime of solar-wind turbulence.

Recent observations of the solar wind have pointed out the existence of a cascade of magnetic energy from the scale of the proton Larmor radius ρ(p) down to the electron Larmor radius ρ(e) scale. In this Letter we study the spatial properties of magnetic field fluctuations in the solar wind and find that at small scales the magnetic field does not resemble a sea of homogeneous fluctuations, but rather a two-dimensional plane containing thin current sheets and discontinuities with spatial sizes ranging from l >/~ ρ(p) down to ρ(e) and below. These isolated structures may be manifestations of intermittency that localize sites of turbulent dissipation. Studying the relationship between turbulent dissipation, reconnection, and intermittency is crucial for understanding the dynamics of laboratory and astrophysical plasmas.

Wave-vector dependence of magnetic-turbulence spectra in the solar wind.

Using four-point measurements of the Cluster spacecraft, the energy distribution was determined for magnetic field fluctuations in the solar wind directly in the three-dimensional wave-vector domain in the range |k|

Three dimensional anisotropic κ spectra of turbulence at subproton scales in the solar wind.

We show the first three dimensional (3D) dispersion relations and k spectra of magnetic turbulence in the solar wind at subproton scales. We used the Cluster data with short separations and applied the k-filtering technique to the frequency range where the transition to subproton scales occurs. We show that the cascade is carried by highly oblique kinetic Alfvén waves with ω(plas) ≤ 0.1ω(ci) down to k(⊥) ρ(i)∼2. Each k spectrum in the direction perpendicular to B0 shows two scaling ranges separated by a breakpoint (in the interval [0.4,1]k(⊥)ρ(i): a Kolmogorov scaling k(⊥)⁻¹â±7 followed by a steeper scaling ∼k(⊥)⁻4ⁱ5. We conjecture that the turbulence undergoes a transition range, where part of the energy is dissipated into proton heating via Landau damping and the remaining energy cascades down to electron scales where electron Landau damping may predominate.

Evidence of a cascade and dissipation of solar-wind turbulence at the electron gyroscale.

We report the first direct determination of the dissipation range of magnetofluid turbulence in the solar wind at the electron scales. Combining high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectrum of turbulence and found two distinct breakpoints in the magnetic spectrum at 0.4 and 35 Hz, which correspond, respectively, to the Doppler-shifted proton and electron gyroscales, f(rho p) and f(rho e). Below f(rho p), the spectrum follows a Kolmogorov scaling f (-1.62), typical of spectra observed at 1 AU. Above f (rho p), a second inertial range is formed with a scaling f;{-2.3} down to f (rho e). Above f (rho e), the spectrum has a steeper power law approximately f (-4.1) down to the noise level of the instrument. We interpret this as the dissipation range and show a remarkable agreement with theoretical predictions of a quasi-two-dimensional cascade into Kinetic Alfvén Waves (KAW).

Kinetic Alfvén Wave Turbulence and Transport through a Reconnection Diffusion Region.

We demonstrate from observations that kinetic Alfvén waves may play an important role in facilitating magnetic reconnection. These waves radiate outwards from the diffusion region oblique to the magnetic field in a conelike pattern delimited by the X line separatrices with outward energy fluxes equivalent to that contained in the outstreaming ions. It is shown that the wave vectors reverse across the X and symmetry lines and have a large out of plane component. We estimate that these waves drive significant transport through the diffusion region.

Mode conversion and anomalous transport in Kelvin-Helmholtz vortices and kinetic Alfvén waves at the Earth's magnetopause.

Observations at the Earth's magnetopause identify mode conversion from surface to kinetic Alfvén waves at the Alfvén resonance. Kinetic Alfvén waves radiate into the magnetosphere from the resonance with parallel scales up to the order of the geomagnetic field-line length and spectral energy densities obeying a k(perpendicular)(-2.4) power law. Amplitudes at the Alfvén resonance are sufficient to both demagnetize ions across the magnetopause and provide field-aligned electron bursts. These waves provide diffusive transport across the magnetopause sufficient for boundary layer formation.

Drift-kinetic Alfvén waves observed near a reconnection X line in the earth's magnetopause.

We identify drift-kinetic Alfvén waves in the vicinity of a reconnection X line on the Earth's magnetopause. The dispersive properties of these waves have been determined using wavelet interferometric techniques applied to multipoint observations from the Cluster spacecraft. Comparison of the observed wave dispersion with that expected for drift-kinetic Alfvén waves shows close agreement. The waves propagate outwards from the X line suggesting that reconnection is a kinetic Alfvén wave source. Energetic O+ ions observed in these waves indicate that reconnection is a driver of auroral ion outflow.

Shopping for health information.

In this time of ongoing health care changes, consumers need to become better informed to actively participate in their health care decisions. As a result, hospital libraries are being challenged to address this need. Scottsdale Healthcare's Health Sciences Libraries have responded to this challenge by establishing a Health Information Center at the premiere shopping mall in the area. Implementing a Health Information Center at a mall is a unique way to bring medical information to the community. The purpose of this paper is to describe the planning process, the implementation, and the future vision of the Health Information Center at Scottsdale Fashion Square.

Significance of cell groups in voided urine.

OBJECTIVE: To determine the significance of different types of cell groups in voided urine for diagnosing transitional cell carcinoma (TCC). STUDY DESIGN: We reviewed voided urine specimens, with corresponding biopsies taken within 120 days after urine collection, for cell groups. Type and number of cell groups were correlated with the histologic diagnoses. RESULTS: Of 5,001 voided urine specimens, 134 (3%) had corresponding biopsies. Flat sheets were significantly more common in urine specimens with corresponding negative biopsies (24%) than in those with biopsies showing TCC (6%) (chi 2 P = .0032). The incidence of collared, three-dimensional cell groups was low (0-7%) and not associated with biopsy findings. Irregular, three-dimensional cell groups were more common than collared cell groups and were most common in cases with invasive TCC on biopsy (38%). While this was statistically significantly more common than in urines associated with negative biopsies (17%) (chi 2 P = .0499), it was not specific. Requiring three or more irregular cell groups did not improve discrimination between TCC and benign cases. Cell groups of any type or number were not more common in cases associated with grade 1 papillary TCC than negative biopsies. Diagnoses associated with multiple irregular, three-dimensional cell groups and a negative biopsy included medullary sponge kidney, hemorrhagic cystitis, cystitis not otherwise specified, and urolithiasis. CONCLUSION: Irregular, three-dimensional cell groups were most common in voided urine from patients with invasive TCC, but the identification of cell groups of any type in voided urine had little diagnostic utility.

Implementing national standards for cancer pain management: program model and evaluation.

The purpose of this quasi-experimental (pre and posttest) study was to test a model pain management program (PMP) to implement the American Pain Society (APS) quality assurance standards for the management of acute and chronic cancer pain using a continuous quality improvement (CQI) approach to improve professionals' knowledge and skills, patient satisfaction, and to identify areas needing improvement. The sample consisted of 1210 nurse responses and 698 interviews of patients with pain during hospitalization at a major urban cancer center. The PMP provided a structure (standards), educational opportunities, and training in CQI methods. Outcome measures included a patient evaluation questionnaire and concerns checklist; nurse knowledge, attitude and barriers questionnaire; and focus groups to identify areas needing improvement. Significant improvements were found in patients' satisfaction, nurses' knowledge and attitude scores, and reductions in nurses' perceptions of barriers. Focus groups revealed the need for improved communication among disciplines about pain and better assessment of patients unable to self-report. The program met its goal of implementing the APS standards, educating nurses, and identifying "system" problems, and improving overall patient satisfaction.

Graves' disease and autoimmune factor VIII deficiency.

A patient with longstanding Hashimoto's thyroiditis who was treated with L-thyroxine at a dosage of 0.05 mg/day developed a decreased serum TSH concentration. L-Thyroxine was discontinued. Within 1 month, the patient developed mild hyperthyroidism due to Graves' disease. A hemorrhagic disorder occurred simultaneously with bleeding into muscle, joints, and skin. The bleeding disorder was identified as an acquired factor VIII deficiency due to a factor VIII inhibitor. The bleeding disorder resolved after treatment with prednisone, cyclophosphamide, and intravenous gamma globulin. Graves' disease also resolved but without specific treatment with either antithyroid drugs or radioactive iodine. The development of these two autoimmune disorders in this patient simultaneously suggests an underlying derangement in immune regulation common to both diseases.