Pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol

Molecular dynamics simulations are obtained and analyzed to study pairing of 1-hexyl-3-methylimidazolium and tetrafluoroborate ions in n-pentanol, in particular by evaluating the potential-of-mean-force between counter ions. The present molecular model and simulation accurately predicts the dissociation constant Kd in comparison to experiment, and thus the behavior and magnitudes for the ion-pair pmf at molecular distances, even though the dielectric constant of the simulated solvent differs from the experimental value by about 30%. A naive dielectric model does not capture molecule structural effects such as multiple conformations and binding geometries of the Hmim+ and BF4- ion-pairs. Mobilities identify multiple time-scale effects in the autocorrelation of the random forces on the ions, and specifically a slow, exponential time-decay of those long-ranged forces associated here with dielectric friction effects.Comment: 5 pages, 7 figures. V2: Figs. 4 & 7 redrawn for better visual clarity with log-scales. No change in results. In press J. Chem. Phys. 201

Nondegenerate Fermions in the Background of the Sphaleron Barrier

We consider level crossing in the background of the sphaleron barrier for nondegenerate fermions. The mass splitting within the fermion doublets allows only for an axially symmetric ansatz for the fermion fields. In the background of the sphaleron we solve the partial differential equations for the fermion functions. We find little angular dependence for our choice of ansatz. We therefore propose a good approximate ansatz with radial functions only. We generalize this approximate ansatz with radial functions only to fermions in the background of the sphaleron barrier and argue, that it is a good approximation there, too.Comment: LATEX, 20 pages, 11 figure

Asymmetric gate induced drain leakage and body leakage in vertical MOSFETs with reduced parasitic capacitance

Vertical MOSFETs, unlike conventional planar MOSFETs, do not have identical structures at the source and drain, but have very different gate overlaps and geometric configurations. This paper investigates the effect of the asymmetric source and drain geometries of surround-gate vertical MOSFETs on the drain leakage currents in the OFF-state region of operation. Measurements of gate-induced drain leakage (GIDL) and body leakage are carried out as a function of temperature for transistors connected in the drain-on-top and drain-on-bottom configurations. Asymmetric leakage currents are seen when the source and drain terminals are interchanged, with the GIDL being higher in the drain-on-bottom configuration and the body leakage being higher in the drain-on-top configuration. Band-to-band tunneling is identified as the dominant leakage mechanism for both the GIDL and body leakage from electrical measurements at temperatures ranging from ?50 to 200?C. The asymmetric body leakage is explained by a difference in body doping concentration at the top and bottom drain–body junctions due to the use of a p-well ion implantation. The asymmetric GIDL is explained by the difference in gate oxide thickness on the vertical (110) pillar sidewalls and the horizontal (100) wafer surface

Insights into Pharmacotherapy Management for Parkinson's Disease Patients Using Wearables Activity Data.

We investigate what supervised classification models using clinical and wearables data are best suited to address two important questions about the management of Parkinson's Disease (PD) patients: 1) does a PD patient require pharmacotherapy or not, and 2) whether therapies are having an effect. Currently, patient management is suboptimal due to using subjective patient reported episodes to answer these questions. METHODOLOGY: Clinical and real environment sensor data (memory, tapping, walking) was provided by the mPower study (6805 participants). From the data, we derived relevant clinical scenarios: S1) before vs. after initiating pharmacotherapy, and S2) before vs. after taking medication. For each scenario we designed and tested 6 methods of supervised classification. Precision, Accuracy and Area Under the Curve (AUC) were computed using 10-fold cross-validation. RESULTS: The best classification models were: S1) Decision Trees on Tapping activity data (AUC 0.95, 95% CI 0.05); and S2) K-Nearest Neighbours on Gait data (mean AUC 0.70, 95% CI 0.07, 46% participants with AUC > 0.70). CONCLUSIONS: Automatic patient classification based on sensor activity data can objectively inform PD medication management, with significant potential for improving patient care

Level Crossing Along Sphaleron Barriers

In the electroweak sector of the standard model topologically inequivalent vacua are separated by finite energy barriers, whose height is given by the sphale\-ron. For large values of the Higgs mass there exist several sphaleron solutions and the barriers are no longer symmetric. We construct paths of classical configurations from one vacuum to a neighbouring one and solve the fermion equations in the background field configurations along such paths, choosing the fermions of a doublet degenerate in mass. As in the case of light Higgs masses we observe the level crossing phenomenon also for large Higgs masses.Comment: 17 pages, latex, 10 figures in uuencoded postscript files. THU-94/0

Comparison between two methods of solution of coupled equations for low-energy scattering

Cross sections from low-energy neutron-nucleus scattering have been evaluated using a coupled channel theory of scattering. Both a coordinate-space and a momentum-space formalism of that coupled-channel theory are considered.A simple rotational model of the channel interaction potentials is used to find results using two relevant codes, ECIS97 and MCAS, so that they may be compared. The very same model is then used in the MCAS approach to quantify the changes that occur when allowance is made for effects of the Pauli principle.Comment: 6 pages, 3 figure

UV induces resistance in Arabidopsis Thaliana to the Oomycete Pathogen Hyaloperonospora Parasitica

Owing to their sessile nature, plants have evolved mechanisms to minimise the damaging effects of abiotic and biotic stresses. Attack by pathogenic fungi, viruses and bacterium is a major type of biotic stress. To resist infection, plants recognise invading pathogens and induce disease resistance through multiple signal transduction pathways. In addition, appropriate stimulation can cause plants to increase their resistance to future pathogen attack. We have found that exposure to non-lethal doses of UV-C (254 nm) renders a normally susceptible ecotype of Arabidopsis thaliana resistant to the biotrophic Oomycete pathogen Hyaloperonospora parasitica. The UV treatment induces an incompatible response in a dose-dependent fashion, and is still effective upon pathogen inoculation up to seven days after UV exposure. The degree of resistance diminishes with time but higher doses result in greater levels of resistance, even after seven days. Furthermore, the effect is systemic, occurring in parts of the plant that have not been irradiated. Incubation in the dark post?irradiation and prior to infection reduces the UV dose required to generate a specific level of pathogen resistance without affecting the duration of resistance. These observations, plus the inability of plants to photoreactivate UV photoproducts in the dark, strongly suggest that DNA damage induces the resistance phenotype. Currently, we are assessing the influence of DNA repair defects on UV-induced resistance, following the expression of a number of defence?related genes post-UV-C irradiation, and assessing the effect of UV in plant mutants deficient in specific signalling molecules involved in resistance.<br /

Frustrated magnets in three dimensions: a nonperturbative approach

Frustrated magnets exhibit unusual critical behaviors: they display scaling laws accompanied by nonuniversal critical exponents. This suggests that these systems generically undergo very weak first order phase transitions. Moreover, the different perturbative approaches used to investigate them are in conflict and fail to correctly reproduce their behavior. Using a nonperturbative approach we explain the mismatch between the different perturbative approaches and account for the nonuniversal scaling observed.Comment: 7 pages, 1 figure. IOP style files included. To appear in Journal of Physics: Condensed Matter. Proceedings of the conference HFM 2003, Grenoble, Franc