One Solution for Managing Risks during Cutbacks in Residency Training Programs

Professors Knott and Ruroede examine the risks associated with downsizing and elimination of physician residency training programs

Signatures of ring currents in a magnetic mirror plasma experiment

Spatial profiles of electron density and temperature obtained from Langmuir probe data in a magnetic mirror plasma experiment using permanent rare-earth magnet stacks show clear signatures of azimuthal or ring currents generated by grad B and curvature drifts. The plasma-generating hot cathode filament is placed within the mirror so that the primary electrons generated with energies sime75 eV are confined by the magnetic mirror effect resulting in a combination of a rapid bounce motion with a slower azimuthal drift whose direction is determined by the orientation of the magnet stacks. A spatial scan using a movable Langmuir probe system shows two peaks of unequal amplitude in the hot electron density profile at locations along the probe path corresponding to phgr = 90° and phgr = 270° where the filament is located at phgr = 0. The position of the stronger peak is consistent with the shorter path in the electron drift direction for the choice of orientation of the magnets. Reversing the magnetic orientation exchanges the locations of the strong and weak hot electron density peaks. The dependence of the ratio of the two peak amplitudes on gas pressure p is consistent with exponential attenuation of the hot electron density along the drift orbit with a mean free path λ mfp ∝ 1/p

UK general election preview: what to look out for as Britain goes to the polls

The UK’s snap election on 8 June initially looked like being a comfortable victory for Theresa May and the Conservatives, but with the polls tightening in the last few weeks, there is now far more uncertainty about the outcome. We asked some of our contributors for their reflections on the campaign and the key things to watch out for when the results come in. Patrick Dunleavy: Three things we’ve learned already from the 2017 campaign turnaround Eunice Goes: Corbyn will lose the election, but he has already changed British politics Thomas J. Leeper: The Brexit election that never was Eleanor Knott: EU citizens – taxation, but no representation Isabelle Hertner: The Liberal Democrats’ pro-EU campaign has fallen flat Stuart Brown: The SNP will win in Scotland, but the story of the night might well be the revival of Scottish Labour Julian Göpffarth: The view from Germany – a longing for British pragmatis

Measurement and parameterization of sub-1 eV ion temperatures in a helium plasma confined by a magnetic mirror

Using a magnetic mirror plasma device, helium ion temperatures were investigated using high resolution Doppler spectroscopy of the He II line at 468.6 nm. The objective was to improve the quality of fits to Langmuir probe data. Measured temperatures, which represent an average value over a line of sight, ranged from 0.07 eV to 0.32 eV with higher values reached in stronger magnetic fields. An analytic expression for the line of sight integral of a variable width Gaussian signal is presented, and it is demonstrated that the integrated signal can, in practice, be accurately fitted by a single Gaussian line shape. A large number of spectra was acquired using a randomized experimental design with four independently controllable engineering variables and three discrete magnetic fields. Separate parameterizations of the results for each magnetic field in terms of the engineering variables showed that the data could already be well fitted using only the plasma current as a predictor. The fit to the ion temperature data was significantly improved when both the plasma current and filament bias voltage were used as predictors. The helium gas fill pressure had negligible predictive value for the ion temperature

Nigrostriatal overabundance of α-synuclein leads to decreased vesicle density and deficits in dopamine release that correlate with reduced motor activity

α-Synuclein (α-syn) is a presynaptic protein present at most nerve terminals, but its function remains largely unknown. The familial forms of Parkinson's disease associated with multiplications of the α-syn gene locus indicate that overabundance of this protein might have a detrimental effect on dopaminergic transmission. To investigate this hypothesis, we use adeno-associated viral (AAV) vectors to overexpress human α-syn in the rat substantia nigra. Moderate overexpression of either wild-type (WT) or A30P α-syn differs in the motor phenotypes induced, with only the WT form generating hemiparkinsonian impairments. Wild-type α-syn causes a reduction of dopamine release in the striatum that exceeds the loss of dopaminergic neurons, axonal fibers, and the reduction in total dopamine. At the ultrastructural level, the reduced dopamine release corresponds to a decreased density of dopaminergic vesicles and synaptic contacts in striatal terminals. Interestingly, the membrane-binding-deficient A30P mutant does neither notably reduce dopamine release nor it cause ultrastructural changes in dopaminergic axons, showing that α-syn's membrane-binding properties are critically involved in the presynaptic defects. To further determine if the affinity of the protein for membranes determines the extent of motor defects, we compare three forms of α-syn in conditions leading to pronounced degeneration. While membrane-binding α-syns (wild-type and A53T) induce severe motor impairments, an N-terminal deleted form with attenuated affinity for membranes is inefficient in inducing motor defects. Overall, these results demonstrate that α-syn overabundance is detrimental to dopamine neurotransmission at early stages of the degeneration of nigrostriatal dopaminergic axon