From a few to many electrons in quantum dots under strong magnetic fields: Properties of rotating electron molecules with multiple rings

Using the method of breaking of circular symmetry and of subsequent symmetry restoration via projection techiques, we present calculations for the ground-state energies and excitation spectra of N-electron parabolic quantum dots in strong magnetic fields in the medium-size range 10 <= N <= 30. The physical picture suggested by our calculations is that of finite rotating electron molecules (REMs) comprising multiple rings, with the rings rotating independently of each other. An analytic expression for the energetics of such non-rigid multi-ring REMs is derived; it is applicable to arbitrary sizes given the corresponding equilibrium configuration of classical point charges. We show that the rotating electron molecules have a non-rigid (non-classical) rotational inertia exhibiting simultaneous crystalline correlations and liquid-like (non-rigidity) characteristics. This mixed phase appears in high magnetic fields and contrasts with the picture of a classical rigid Wigner crystal in the lowest Landau level.Comment: REVTEX4, 15 pages with 12 figures. Accepted for publication in Physical Review B. To download a file with figures of higher quality, click http://www.prism.gatech.edu/~ph274cy/ (go to publication #72

End-of-Life Decisions, Ethics and the Law

This position paper puts forward an ethical case for end-of-life decision-mak¬ing legislation. Such legislation would clarify areas of legal uncertainty, most notably in respect of terminal pain management, withholding and withdrawal of life-sustaining treatment (sometimes called “passive euthanasia”), and advance directives (a living will and a durable power of attorney for healthcare). More controversially, the paper also argues for the inclusion of assisted dying (assisted suicide and voluntary active euthanasia) in a comprehensive end-of-life decision-making bill

Physician-assisted suicide and voluntary euthanasia - a response

No Abstrac

Fiber Orientation Estimation Guided by a Deep Network

Diffusion magnetic resonance imaging (dMRI) is currently the only tool for noninvasively imaging the brain's white matter tracts. The fiber orientation (FO) is a key feature computed from dMRI for fiber tract reconstruction. Because the number of FOs in a voxel is usually small, dictionary-based sparse reconstruction has been used to estimate FOs with a relatively small number of diffusion gradients. However, accurate FO estimation in regions with complex FO configurations in the presence of noise can still be challenging. In this work we explore the use of a deep network for FO estimation in a dictionary-based framework and propose an algorithm named Fiber Orientation Reconstruction guided by a Deep Network (FORDN). FORDN consists of two steps. First, we use a smaller dictionary encoding coarse basis FOs to represent the diffusion signals. To estimate the mixture fractions of the dictionary atoms (and thus coarse FOs), a deep network is designed specifically for solving the sparse reconstruction problem. Here, the smaller dictionary is used to reduce the computational cost of training. Second, the coarse FOs inform the final FO estimation, where a larger dictionary encoding dense basis FOs is used and a weighted l1-norm regularized least squares problem is solved to encourage FOs that are consistent with the network output. FORDN was evaluated and compared with state-of-the-art algorithms that estimate FOs using sparse reconstruction on simulated and real dMRI data, and the results demonstrate the benefit of using a deep network for FO estimation.Comment: A shorter version is accepted by MICCAI 201

Coronal and chromospheric physics

Achievements and completed results are discussed for investigations covering solar activity during the solar maximum mission and the solar maximum year; other studies of solar activity and variability; infrared and submillimeter photometry; solar-related atomic physics; coronal and transition region studies; prominence research; chromospheric research in quiet and active regions; solar dynamics; eclipse studies; and polarimetry and magnetic field measurements. Contributions were also made in defining the photometric filterograph instrument for the solar optical telescope, designing the combined filter spectrograph, and in expressing the scientific aims and implementation of the solar corona diagnostic mission

Wool versus mutton in extensive grazing areas

This paper investigates the relative profitability of woolled and mutton sheep under field conditions in an extensive grazing area. The dataset comprises 34 fulltime farmers and 75% of the sheep in the district. There was no difference in unit production costs or net farm income per sheep in the flock. Dorper flocks recorded higher lambing rates and Merinos lower rates of predation, which deserves further investigation. The percentage woolled sheep in the flock was modelled as a logit function of farm size, crop area, tradition and terrain ruggedness, although the latter was not significant. These results confirm earlier recommendations that reproductive efficiency must be carefully monitored in Merino flocks. The extension message is that on average there is no financial advantage to woolled sheep production, although this could change if woolled flocks could be made more productive. The wool industry must not stop serving these extremely arid areas.Keywords: financial performance, sheep breeds, arid conditions, extension implication

Coronal and chromospheric physics

The Solar Maximum Mission support program is mentioned along with investigations of the solar corona, prominences, and chromosphere. The solar limb was studied using far infrared and submillimeter photometry. Stokes profiles obtained from sunspot observations were examined with a polarimetric technique