Polar plasmas as observed by Dynamics Explorers 1 and 2

Plasma measurements from the Dynamics Explorer 1 and 2 satellites were used to characterize the polar cap environment. Analysis of numerous polar-cap passes indicate that, in general, three major regimes of plasma exist: (1) polar rain--electrons with magnetosheath-like energy spectra but much lower densities, most intense near the cusp and weakening toward the central polar cap; (2) polar wind--low energy upward flowing ions with both field-aligned and conical distributions; and (3) acceleration events--sporadic events consistent with the acceleration of electrons and positive ions by parallel electric fields. (1) to (3) were observed at high altitudes by Dynamics Explorer 1, while (1) and (3) were also observed at low altitudes by Dynamics Explorer 2. The plasma parameters associated with these plasma regimes are presented and discussed in terms of source and acceleration mechanisms

Smoking, dementia and cognitive decline in the elderly, a systematic review.

Background. Nicotine may aid reaction time, learning and memory, but smoking increases cardiovascular risk. Cardiovascular risk factors have been linked to increased risk of dementia. A previous meta-analysis found that current smokers were at higher risk of subsequent dementia, Alzheimers disease, vascular dementia and cognitive decline. Methods. In order to update and examine this further a systematic review and meta-analysis was carried out using different search and inclusion criteria, database selection and more recent publications. Both reviews were restricted to those aged 65 and over. Results. The review reported here found a significantly increased risk of Alzheimers disease with current smoking and a likely but not significantly increased risk of vascular dementia, dementia unspecified and cognitive decline. Neither review found clear relationships with former smoking. Conclusion. Current smoking increases risk of Alzheimers disease and may increase risk of other dementias. This reinforces need for smoking cessation, particularly aged 65 and over. Nicotine alone needs further investigation. © 2008 Peters et al; licensee BioMed Central Ltd

Small portable speed calculator

Calculator is adapted stopwatch calibrated for fast accurate measurement of speeds. Single assembled unit is rugged, self-contained, and relatively inexpensive to manufacture. Potential market includes automobile-speed enforcement, railroads, and field-test facilities

Hadron Spectroscopy with Dynamical Chirally Improved Fermions

We simulate two dynamical, mass degenerate light quarks on 16^3x32 lattices with a spatial extent of 2.4 fm using the Chirally Improved Dirac operator. The simulation method, the implementation of the action and signals of equilibration are discussed in detail. Based on the eigenvalues of the Dirac operator we discuss some qualitative features of our approach. Results for ground state masses of pseudoscalar and vector mesons as well as for the nucleon and delta baryons are presented.Comment: 26 pages, 17 figures, 10 table

The equation of state with nonzero chemical potential for 2+1 flavors

We present results for the QCD equation of state with nonzero chemical potential using the Taylor expansion method with terms up to sixth order in the expansion. Our calculations are performed on asqtad 2+1 quark flavor lattices at $N_t=4$.Comment: Talk given at the XXV International Symposium on Lattice Field Theory, July 30-4 August 2007, Regensburg, German

Dynamic phenomena in superconducting oxides by ESR

Dynamic electron spin resonance (ESR) measurements compare the paramagnetic and antiferromagnetic (AF) properties of superconducting oxides in the range 4 K to room temperature, at 8 MHz and 9.36 GHz. Two are derivatives of YBa2Cu30 7: 1: Nd(Nd0.05Ba0.95 )2Cu30 7, Te0 =72 K and II: Y0.2Cao.8Sr2[Cu2(Tlo.5Pb0.5 )]07, Te0 =108 K and two are cases where AF ordering dominates the weak superconductivity: III: Nb01.1\u3e 1. 25 ~Teo~ 10 K and IV: La2Ni04.00, 70 K :::: Teo:::: 40 K. At temperatures 298:::: T:::: 64 K, the ESR absorption by I indicates orthorhombic symmetry. The peaks at Ke =2.06, gb =2.13, and Ka =2.24 are identified with the presence of 5% Nd3+( 41912 ) in the Ba layer because the characteristic Cu2+ impurity hyperfine structure is absent and the ESR signal disappears several degrees below Te. Near Te the ESR absorption is reduced by two orders of magnitude. Proximity effects give rise to interference fringes with period r1 ( T) independent of the field B and the rate of sweep dBzldt. ESR is observed below Te because flux penetrates the superconductor. The temperature dependence of r1 leads to an activation energy for the flux motion E0 (1)/R ~ 16 K and Ea (111)/R ~3 K =Te /4. In the superconducting state a coherent flux expulsion response to a change in B. from 500 mT to zero is observed in times T, = 8 to 10 s. The inverse rate of noise spikes due to flux expulsion, when the samples are cooled through Te in a magnetic field, varies from Tnoise=3.5 s for III to 21 s for IV. The microwave absorption spectra identify three temperature regimes: (i) For 3.5 K \u3c T \u3c T m T* \u3c Teo superconducting behavior was confirmed by the energy loss near zero magnetic field and the kinetics of high-field noise due to flux expulsion. Near g =2.00 ESR absorption is observed for all materials. A broad absorption near 50 to 100 mT at 9.36 GHz has been attributed to AF resonance. (ii) T m T* ~ T ~ Te identifies the range where flux motion gives rise to interference fringes in the ESR absorption. (iii) ESR and AF resonance are observed immediately after warming above Tc

Report from magnetospheric science

By the early 1990s, magnetospheric physics will have progressed primarily through observations made from Explorer-class spacecraft, sounding rockets, ground based facilities, and shuttle based experiments. The global geospace science (GGS) element of the International Solar Terrestrial Physics program, when combined with contributions to the ESA Cluster mission and ground based and computer modeling programs, will form the basis for a major U.S. initiative in magnetospheric physics. The scientific objectives of the GGS program involve the study of energy transport throughout geospace. The Cluster mission will investigate turbulence and boundary phenomena in geospace, particularly at high latitudes on the dayside and in the region of the neutral sheet at geocentric distances of about 20 earth radii on the night side of the earth. The current state of knowledge is reviewed and the goals of these missions are briefly discussed