On the use of electrical ion sources for ion tracer experiments in the magnetosphere

Electric ion source in orbit around earth to generate probes for magnetosphere studies of electric fields, ion diffusion, and distant magnetic field configuratio

Loudness (annoyance), prediction procedure for steady sounds

Method has been devised to predict loudness level of any steady sound solely from its measured power spectrum level. Method is based on assumption that, with respect to loudness sensation, the human auditory system acts as open-loop transmission system with transmittance function determined from measured tone curves

The spatial epidemiology of the Duffy blood group and G6PD deficiency

Over a third of the world’s population lives at risk of potentially severe Plasmodium vivax malaria. Unique aspects of this parasite’s biology and interactions with its human host make it harder to control and eliminate than the better studied Plasmodium falciparum parasite. Spatial mapping of two human genetic polymorphisms were developed to support evidence-based targeting of control interventions and therapies. First, to enumerate and map the population at risk of P. vivax infection (PvPAR), the prevalence of this parasite’s human blood cell receptor – the Duffy antigen – was mapped globally. Duffy negative individuals are resistant to infection, and this map provided the means to objectively model the low endemicity of P. vivax across Africa. The Duffy maps helped resolve that only 3% of the global PvPAR was from Africa. The second major research focus was to map the spatial distribution of glucose-6-phosphate dehydrogenase enzyme deficiency (G6PDd), the genetic condition which predisposes individuals to potentially life-threatening haemolysis from primaquine therapy. Despite this drug’s vital role in being the only treatment of relapsing P. vivax parasites, risks of G6PDd-associated haemolysis result in significant under-use of primaquine. G6PDd was found to be widespread, with an estimated frequency of 8.0% (50% CI: 7.4-8.8%) across malarious regions. Third, it was important to represent more detailed descriptions of the genetic diversity underpinning this enzyme disorder, which ranges in phenotype from expressing mild to life-threatening primaquine-induced haemolysis. These variants’ spatial distributions were mapped globally and showed strikingly conspicuous distributions, with widespread A- dominance across Africa, predominance of the Mediterranean variant from the Middle East across to India, and east of India diversifying into a different and diverse array of variants, showing heterogeneity both at regional and community levels. Fourth, the G6PDd prevalence and severity maps were synthesised into a framework assessing the spatial variability of overall risk from G6PDd to primaquine therapy. This found that risks from G6PDd were too widespread and potentially severe to sanction primaquine treatment without prior G6PDd screening, particularly across Asia where the majority of the population are Duffy positive and G6PDd was common and severe. Finally, the conclusions from these studies were discussed and recommendations made for essential further research needed to support current efforts into P. vivax control

Anne Tenney, interviewed by Elizabeth Bunten

Anne Tenney, interviewed by Elizabeth Bunten, May 7, 2003, in Castine, Maine. Smith, age 81, talks about her decision to join the Navy (Women Accepted for Volunteer Emergency Service) in World War II; her basic training experiences; being assigned to New York City; her anti-submarine work; marrying and leaving the service after her pregnancy; remarrying another WWII veteran as a widow; public perception of women in the Navy during the war; minorities in the military; and changes in the role of women in the military. Text: 6 pp. transcript. Recording: No recording.https://digitalcommons.library.umaine.edu/mf144/1087/thumbnail.jp

Magnetic fluctuation power near proton temperature anisotropy instability thresholds in the solar wind

The proton temperature anisotropy in the solar wind is known to be constrained by the theoretical thresholds for pressure anisotropy-driven instabilities. Here we use approximately 1 million independent measurements of gyroscale magnetic fluctuations in the solar wind to show for the first time that these fluctuations are enhanced along the temperature anisotropy thresholds of the mirror, proton oblique firehose, and ion cyclotron instabilities. In addition, the measured magnetic compressibility is enhanced at high plasma beta ($\beta_\parallel \gtrsim 1$) along the mirror instability threshold but small elsewhere, consistent with expectations of the mirror mode. The power in this frequency (the 'dissipation') range is often considered to be driven by the solar wind turbulent cascade, an interpretation which should be qualified in light of the present results. In particular, we show that the short wavelength magnetic fluctuation power is a strong function of collisionality, which relaxes the temperature anisotropy away from the instability conditions and reduces correspondingly the fluctuation power.Comment: 4 pages, 4 figure

Gyrokinetic Simulations of Solar Wind Turbulence from Ion to Electron Scales

The first three-dimensional, nonlinear gyrokinetic simulation of plasma turbulence resolving scales from the ion to electron gyroradius with a realistic mass ratio is presented, where all damping is provided by resolved physical mechanisms. The resulting energy spectra are quantitatively consistent with a magnetic power spectrum scaling of $k^{-2.8}$ as observed in \emph{in situ} spacecraft measurements of the "dissipation range" of solar wind turbulence. Despite the strongly nonlinear nature of the turbulence, the linear kinetic \Alfven wave mode quantitatively describes the polarization of the turbulent fluctuations. The collisional ion heating is measured at sub-ion-Larmor radius scales, which provides the first evidence of the ion entropy cascade in an electromagnetic turbulence simulation.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let

A cross-sectional MR study of body fat volumes and distribution in chronic schizophrenia

People with schizophrenia show higher risk for abdominal obesity than the general population, which could contribute to excess mortality. However, it is unclear whether this is driven by alterations in abdominal fat partitioning. Here, we test the hypothesis that individuals with schizophrenia show a higher proportion of visceral to total body fat measured using magnetic resonance imaging (MRI). We recruited 38 participants with schizophrenia and 38 healthy controls matched on age, sex, ethnicity and body mass index. We found no significant differences in body fat distribution between groups, suggesting that increased abdominal obesity in schizophrenia is not associated with altered fat distribution

Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas

This letter presents the first ab initio, fully electromagnetic, kinetic simulations of magnetized turbulence in a homogeneous, weakly collisional plasma at the scale of the ion Larmor radius (ion gyroscale). Magnetic and electric-field energy spectra show a break at the ion gyroscale; the spectral slopes are consistent with scaling predictions for critically balanced turbulence of Alfven waves above the ion gyroscale (spectral index -5/3) and of kinetic Alfven waves below the ion gyroscale (spectral indices of -7/3 for magnetic and -1/3 for electric fluctuations). This behavior is also qualitatively consistent with in situ measurements of turbulence in the solar wind. Our findings support the hypothesis that the frequencies of turbulent fluctuations in the solar wind remain well below the ion cyclotron frequency both above and below the ion gyroscale.Comment: 4 pages, 3 figures, submitted to Physical Review Letter

He Wandered Down The Beaten Path : Song and Chorus

https://digitalcommons.library.umaine.edu/mmb-vp/1560/thumbnail.jp