Relating near-Earth observations of an interplanetary coronal mass ejection to the conditions at its site of origin in the solar corona

A halo coronal mass ejection (CME) was detected on January 20, 2004. We use solar remote sensing data (SOHO, Culgoora) and near-Earth in situ data (Cluster) to identify the CME source event and show that it was a long duration flare in which a magnetic flux rope was ejected, carrying overlying coronal arcade material along with it. We demonstrate that signatures of both the arcade material and the flux rope material are clearly identifiable in the Cluster and ACE data, indicating that the magnetic field orientations changed little as the material traveled to the Earth, and that the methods we used to infer coronal magnetic field configurations are effective

Measurement of the electric fluctuation spectrum of magnetohydrodynamic turbulence

Magnetohydrodynamic (MHD) turbulence in the solar wind is observed to show the spectral behavior of classical Kolmogorov fluid turbulence over an inertial subrange and departures from this at short wavelengths, where energy should be dissipated. Here we present the first measurements of the electric field fluctuation spectrum over the inertial and dissipative wavenumber ranges in a $\beta \gtrsim 1$ plasma. The $k^{-5/3}$ inertial subrange is observed and agrees strikingly with the magnetic fluctuation spectrum; the wave phase speed in this regime is shown to be consistent with the Alfv\'en speed. At smaller wavelengths $k \rho_i \geq 1$ the electric spectrum is softer and is consistent with the expected dispersion relation of short-wavelength kinetic Alfv\'en waves. Kinetic Alfv\'en waves damp on the solar wind ions and electrons and may act to isotropize them. This effect may explain the fluid-like nature of the solar wind.Comment: submitted; 4 pages + 3 figure

The composition of heavy molecular ions inside the ionopause of Comet Halley

The RPA2-PICCA instrument aboard the Giotto spacecraft obtained 10-210 amu mass spectral of cold thermal molecular ions in the coma of Comet Halley. The dissociation products of the long chain formaldehyde polymer polyoxymethylene (POM) have recently been proposed as the dominant complex molecules in the coma of Comet Halley; however, POM alone cannot account for all of the features of the high resolution spectrum. An important component of the dust at Comet Halley is particles highly enriched in carbon, hydrogen, oxygen, and nitrogen relative to the composition of carbonaceous chondrites. Since this dust could be a source for the heavy molecules observed by PICCA, a search was conducted for other chemical species by determining all the molecules with mass between 20 and 120 amu which can be made from the relatively abundant C, H, O, and N, without regard to chemical structure

In situ evidence for the structure of the magnetic null in a 3D reconnection event in the Earth's magnetotail

Magnetic reconnection is one of the most important processes in astrophysical, space and laboratory plasmas. Identifying the structure around the point at which the magnetic field lines break and subsequently reform, known as the magnetic null point, is crucial to improving our understanding reconnection. But owing to the inherently three-dimensional nature of this process, magnetic nulls are only detectable through measurements obtained simultaneously from at least four points in space. Using data collected by the four spacecraft of the Cluster constellation as they traversed a diffusion region in the Earth's magnetotail on 15 September, 2001, we report here the first in situ evidence for the structure of an isolated magnetic null. The results indicate that it has a positive-spiral structure whose spatial extent is of the same order as the local ion inertial length scale, suggesting that the Hall effect could play an important role in 3D reconnection dynamics.Comment: 14 pages, 4 figure

Modulation of constant light effects on the eye by ciliary ganglionectomy and optic nerve section

AbstractOur previous studies have shown that an environment of constant light (CL) can lead to development of high degree of hyperopia in newborn chicks by inducing severe corneal flattening, and compensatory growth of the vitreous chamber. We wish to know whether the abnormal eye growth and progressive hyperopia under CL conditions is accomplished by a mechanism that uses the visual processing pathways of the central nervous system (CNS) or by a mechanism located in the eye. Thirty white leghorn chicks (Cornell K-strain) were raised under 12 h light/12 h dark (12L/12D) for either optic nerve section (ONS) or ciliary ganglion section (CGS). Another 30 chicks were raised under CL for ONS or CGS. Refractive states and corneal curvatures were measured by infrared (IR) photoretinoscopy and IR keratometry, respectively. The axial lengths of the ocular components were measured by A-scan ultrasonography. Both ONS and CGS surgery produced dilated pupils and accommodative paralysis. Four weeks after surgery, CGS eyes exhibited a hyperopic defocus, flatter cornea, and shorter vitreous chamber depth under both CL and normal conditions, whereas ONS eyes showed a smaller radius of corneal curvature and shallow vitreous chamber only in the normal light cycle group. CGS eyes of CL chicks showed significantly deeper vitreous chambers than did fellow control eyes. Our results indicate that optic nerve section does not seem to influence CL effects. Thus, local mechanisms may play a major role in the ocular development of chicks. The ciliary nerve is necessary for the normal corneal and anterior chamber growth, and prevents CL effects. The progressively increasing vitreous chamber depth under CL may be influenced by both local and central mechanisms

Satellite Observations of Separator Line Geometry of Three-Dimensional Magnetic Reconnection

Detection of a separator line that connects magnetic nulls and the determination of the dynamics and plasma environment of such a structure can improve our understanding of the three-dimensional (3D) magnetic reconnection process. However, this type of field and particle configuration has not been directly observed in space plasmas. Here we report the identification of a pair of nulls, the null-null line that connects them, and associated fans and spines in the magnetotail of Earth using data from the four Cluster spacecraft. With di and de designating the ion and electron inertial lengths, respectively, the separation between the nulls is found to be ~0.7di and an associated oscillation is identified as a lower hybrid wave with wavelength ~ de. This in situ evidence of the full 3D reconnection geometry and associated dynamics provides an important step toward to establishing an observational framework of 3D reconnection.Comment: 10 pages, 3 figures and 1 tabl

Performance-Based Financing Empowers Health Workers Delivering Prevention of Vertical Transmission of HIV Services and Decreases Desire to Leave in Mozambique

Background Despite increased access to treatment and reduced incidence, vertical transmission of HIV continues to pose a risk to maternal and child health in sub-Saharan Africa. Performance-based financing (PBF) directed at healthcare providers has shown potential to improve quantity and quality of maternal and child health services. However, the ways in which these PBF initiatives lead to improved service delivery are still under investigation. Methods Therefore, we implemented a longitudinal-controlled proof-of-concept PBF intervention at health facilities and with community-based associations focused on preventing vertical transmission of HIV (PVT) in rural Mozambique. We hypothesized that PBF would increase worker motivation and other aspects of the workplace environment in order to achieve service delivery goals. In this paper, we present two objectives from the PBF intervention with public health facilities (n = 6): first, we describe the implementation of the PBF intervention and second, we assess the impact of the PBF on health worker motivation, key factors in the workplace environment, health worker satisfaction, and thoughts of leaving. Implementation (objective 1) was evaluated through quantitative service delivery data and multiple forms of qualitative data (eg, quarterly meetings, participant observation (n = 120), exit interviews (n = 11)). The impact of PBF on intermediary constructs (objective 2) was evaluated using these qualitative data and quantitative surveys of health workers (n = 83) at intervention baseline, midline, and endline. Results We found that implementation was challenged by administrative barriers, delayed disbursement of incentives, and poor timing of evaluation relative to incentive disbursement (objective 1). Although we did not find an impact on the motivation constructs measured, PBF increased collegial support and worker empowerment, and, in a time of transitioning implementing partners, decreased against desire to leave (objective 2). Conclusion Areas for future research include incentivizing meaningful quality- and process-based performance indicators and evaluating how PBF affects the pathway to service delivery, including interactions between motivation and workplace environment factors