Electrical treatment of reduced consciousness; experience with coma and Alzheimers's disease

The right median nerve can be stimulated electrically to help arouse the central nervous system for persons with reduced levels of consciousness. The mechanisms of central action include increased cerebral blood flow and raised levels of dopamine. There is 11 years of experience in the USA of using nerve stimulation for acute coma after traumatic brain injury. There is a much longer period of experience by neurosurgeons in Japan with implanted electrodes on the cervical spinal cord for persons in the persistent vegetative state (PVS). But the use of right median nerve electrical stimulation (RMNS) for patients in the subacute and chronic phases of coma is relatively new. Surface electrical stimulation to treat anoxic brain injury as well as traumatic brain injury is evolving. Novel applications of electrical stimulation in Amsterdam have produced cognitive behavioural effects in persons with early and mid-stage Alzheimer's disease employing transcutaneous electrical nerve stimulation (TENS). Improvements in short-term memory and speech fluency have also been noted. Regardless of the aetiology of the coma or reduced level of awareness, electrical stimulation may serve as a catalyst to enhance central nervous system functions. It remains for the standard treatments and modalities to retrain the injured brain emerging from reduced levels of consciousness. © 2005 Psychology Press Ltd

The airflow distortion at instruments sites on the RRS "James Cook"

Wind speed and air-sea flux measurements made from instrumentation on ships are affected by the airflow distortion created by the presence of the ship. The airflow can be eitheraccelerated or decelerated depending on the shape of the ship and the location of the anemometer. The computational fluid dynamics (CFD) package VECTIS was used to examinethe extent of the flow distortion at potential anemometer locations on the foremast platform of the RRS "James Cook". This technique has been previously used to study the airflow over many research ships, but this is believed to be the first time it has been applied to a research ship in the design/build stage.CFD modelling of the airflow over the ship showed that the foremast platform of the RRS "James Cook" is a good location to locate instrumentation and make high quality air-sea flux measurements. The wind speed is decelerated by about 2 % of the freestream wind speed for bow-on flows at well-exposed anemometer sites on the foremast platform. For relative wind directions up to ±30° of the bow the airflow is accelerated by up to 5 %.The ship’s anemometers are located on the main mast and are relatively close to the ship’s large satellite communication radome. For winds within 15° of the bow the wind speeds at these anemometer sites are accelerated by up to about 7 %. For wind directions at ±30° the satellite radome has a significant effect on the flow and the wind speeds will be severely biased, with the magnitude of the bias varying rapidly with wind direction and the angle of pitch of the ship. It is strongly recommended that these anemometers be moved higher up and further away from the mast

The relationship between agency, communion, and neural processes associated with conforming to social influence

Social influence is ubiquitous in our daily lives, influencing our opinions, beliefs, and behaviors. Individual differences may determine who is most likely to conform to the opinions of others. More specifically, individual differences in interdependent and independent self-construal determine an individual's sensitivity to and focus on their social surroundings. Relatedly, society traditionally ascribes and prescribes different levels of agency (independence) and communion (interdependence) to men and women. Here, we examined how individual differences in self-construal, and their congruence with gender expectations, influence how people process and respond to social feedback. Results from independent behavioral and neuroimaging samples show that a stronger interdependent self-construal was associated with increased likelihood of conformity, whereas an independent self-construal was not. Further, neuroimaging data suggests that the relationship between brain activity and conformity is moderated by the congruence of gender stereotypes and self-construal. Specifically, stereotypically congruent women (with stronger interdependence) and men (with stronger independence) showed increased activity in mentalizing regions (and value regions in men) when conforming. Stereotypically incongruent women (with stronger independence) and men (with stronger interdependence) showed decreased mentalizing activity when conforming. These results shed light on underlying (neuro)psychological mechanisms that are associated with conformity among different groups

Vortices and dynamics in trapped Bose-Einstein condensates

I review the basic physics of ultracold dilute trapped atomic gases, with emphasis on Bose-Einstein condensation and quantized vortices. The hydrodynamic form of the Gross-Pitaevskii equation (a nonlinear Schr{\"o}dinger equation) illuminates the role of the density and the quantum-mechanical phase. One unique feature of these experimental systems is the opportunity to study the dynamics of vortices in real time, in contrast to typical experiments on superfluid $^4$He. I discuss three specific examples (precession of single vortices, motion of vortex dipoles, and Tkachenko oscillations of a vortex array). Other unusual features include the study of quantum turbulence and the behavior for rapid rotation, when the vortices form dense regular arrays. Ultimately, the system is predicted to make a quantum phase transition to various highly correlated many-body states (analogous to bosonic quantum Hall states) that are not superfluid and do not have condensate wave functions. At present, this transition remains elusive. Conceivably, laser-induced synthetic vector potentials can serve to reach this intriguing phase transition.Comment: Accepted for publication in Journal of Low Temperature Physics, conference proceedings: Symposia on Superfluids under Rotation (Lammi, Finland, April 2010

Vortex Rings in Fast Rotating Bose-Einstein Condensates

When Bose-Eintein condensates are rotated sufficiently fast, a giant vortex phase appears, that is the condensate becomes annular with no vortices in the bulk but a macroscopic phase circulation around the central hole. In a former paper [M. Correggi, N. Rougerie, J. Yngvason, {\it arXiv:1005.0686}] we have studied this phenomenon by minimizing the two dimensional Gross-Pitaevskii energy on the unit disc. In particular we computed an upper bound to the critical speed for the transition to the giant vortex phase. In this paper we confirm that this upper bound is optimal by proving that if the rotation speed is taken slightly below the threshold there are vortices in the condensate. We prove that they gather along a particular circle on which they are evenly distributed. This is done by providing new upper and lower bounds to the GP energy.Comment: to appear in Archive of Rational Mechanics and Analysi

Non-invasive detection of the evolution of the charge states of a double dot system

Coupled quantum dots are potential candidates for qubit systems in quantum computing. We use a non-invasive voltage probe to study the evolution of a coupled dot system from a situation where the dots are coupled to the leads to a situation where they are isolated from the leads. Our measurements allow us to identify the movement of electrons between the dots and we can also identify the presence of a charge trap in our system by detecting the movement of electrons between the dots and the charge trap. The data also reveals evidence of electrons moving between the dots via excited states of either the single dots or the double dot molecule.Comment: Accepted for publication in Phys. Rev. B. 4 pages, 4 figure

Kinks in the Hartree approximation

The topological defects of the lambda phi^4 theory, kink and antikink, are studied in the Hartree approximation. This allows us to discuss quantum effects on the defects in both stationary and dynamical systems. The kink mass is calculated for a number of parameters, and compared to classical, one loop and Monte Carlo results known from the literature. We discuss the thermalization of the system after a kink antikink collision. A classical result, the existence of a critical speed, is rederived and shown for the first time in the quantum theory. We also use kink antikink collisions as a very simple toy model for heavy ion collisions and discuss the differences and similarities, for example in the pressure. Finally, using the Hartree Ensemble Approximation allows us to study kink antikink nucleation starting from a thermal (Bose Einstein) distribution. In general our results indicate that on a qualitative level there are few differences with the classical results, but on a quantitative level there are some import ones.Comment: 20 pages REVTeX 4, 17 Figures. Uses amsmath.sty and subfigure.sty. Final version, fixed typo in published versio

Further Evidence Suggestive of a Solar Influence on Nuclear Decay Rates

Recent analyses of nuclear decay data show evidence of variations suggestive of a solar influence. Analyses of datasets acquired at the Brookhaven National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt (PTB) both show evidence of an annual periodicity and of periodicities with sidereal frequencies in the neighborhood of 12.25 year^{-1} (at a significance level that we have estimated to be 10^{-17}). It is notable that this implied rotation rate is lower than that attributed to the solar radiative zone, suggestive of a slowly rotating solar core. This leads us to hypothesize that there may be an "inner tachocline" separating the core from the radiative zone, analogous to the "outer tachocline" that separates the radiative zone from the convection zone. The Rieger periodicity (which has a period of about 154 days, corresponding to a frequency of 2.37 year^{-1}) may be attributed to an r-mode oscillation with spherical-harmonic indices l=3, m=1, located in the outer tachocline. This suggests that we may test the hypothesis of a solar influence on nuclear decay rates by searching BNL and PTB data for evidence of a "Rieger-like" r-mode oscillation, with l=3, m=1, in the inner tachocline. The appropriate search band for such an oscillation is estimated to be 2.00-2.28 year^{-1}. We find, in both datasets, strong evidence of a periodicity at 2.11 year^{-1}. We estimate that the probability of obtaining these results by chance is 10^{-12}.Comment: 12 pages, 6 figures, v2 has a color corrected Fig 6, a corrected reference, and a corrected typ

Power Spectrum Analysis of Physikalisch-Technische Bundesanstalt Decay-Rate Data: Evidence for Solar Rotational Modulation

Evidence for an anomalous annual periodicity in certain nuclear decay data has led to speculation concerning a possible solar influence on nuclear processes. We have recently analyzed data concerning the decay rates of Cl-36 and Si-32, acquired at the Brookhaven National Laboratory (BNL), to search for evidence that might be indicative of a process involving solar rotation. Smoothing of the power spectrum by weighted-running-mean analysis leads to a significant peak at frequency 11.18/yr, which is lower than the equatorial synodic rotation rates of the convection and radiative zones. This article concerns measurements of the decay rates of Ra-226 acquired at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. We find that a similar (but not identical) analysis yields a significant peak in the PTB dataset at frequency 11.21/yr, and a peak in the BNL dataset at 11.25/yr. The change in the BNL result is not significant since the uncertainties in the BNL and PTB analyses are estimated to be 0.13/yr and 0.07/yr, respectively. Combining the two running means by forming the joint power statistic leads to a highly significant peak at frequency 11.23/yr. We comment briefly on the possible implications of these results for solar physics and for particle physics.Comment: 15 pages, 13 figure