An approach to epilepsy

The key to understanding and managing epilepsy is to decide whether seizures are genetic/idiopathic or caused by focal brain pathology. The classification of seizures was modified in 2010 after many variations of the original 1981 system and inconclusive debate. Major changes included abandoning many entrenched words and complete rejection of the Focal subsystem. While most of the reasoning is rational, the focal system is described in a long list of terms; general clinicians are therefore faced with a more challenging task than that required for understanding the old classification system. Some of the difficulties include using common words with non-intuitive neurological definitions, ambiguous words and the tendency to merge seizure categorisation with epilepsy. This article highlights some of the fundamental principles in trying to categorise seizures and offers a simplified way of using descriptive words to structure the organisation of Focal seizures. Focal seizures are broken down to A, B and C – an easy-to-remember schema for general clinicians, patients and carers. Words such as ‘Aura’ and ‘Blank stare’ are strategically used to represent old seizure types and how they may be linked in the same patient. Awareness or the lack thereof is explained and how the same patient may have different seizure types and combinations of these. There is less change in the Generalised seizures category, but these are often confused with Focal seizures. Absences are confused with blank stares, while Generalised Tonic-Clonic seizures (GTCSs) are confused with ‘Focal-onset evolving rapidly to GTCSs’. Diagrams to illustrate the concepts of Generalised and Focal are included, as well as tables to demonstrate the differences between seizures that appear similar and points to consider in separating them. Focal seizures may mimic almost any human behaviour. Sorting and grouping the symptoms of Focal seizures with awareness (auras) is covered, along with sorting both the former and those without awareness seizures (As and Bs) by brain lobes. Distinguishing between Generalised and Focal seizures is not merely an academic exercise. It assists in determining the aetiology and has a material impact on the choice of management. Appropriate management of seizures starts with identifying the various seizure types. Time will tell whether or not this new descriptive approach to organisation of seizures makes the task easier and more effective

Construction productivity analysis for asphalt concrete pavement rehabilitation in urban corridors

The results of a constructibility and productivity analysis for the California Department of Transportation Long Life Asphalt Concrete Pavement Rehabilitation Strategies program are presented. With the assistance of California asphalt concrete (AC) paving contractors, the analysis explored the effects on construction productivity of rehabilitation materials, design strategy (crack seat and overlay, full-depth replacement), layer profiles, AC cooling time, resource constraints, and alternative lane closure tactics. Deterministic and stochastic analysis programs were developed. A sensitivity study that examined the construction production capability within a 55-h weekend closure was performed. Weekend closures were also compared with continuous closures. Demolition and AC delivery truck flows were the major constraints limiting the AC rehabilitation production capability. It was concluded from the study that efficient lane closure tactics designed to work with the pavement profile (an minimize the nonworking time to increase the construction product! on efficiency. The results of the study will help road agencies evaluate rehabilitation strategies and tactics with the goal of balancing the maximization of production capability and minimization of traffic delay during urban pavement rehabilitation.open114sciescopu

Stroke risk among patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis

Increased stroke risk among chronic obstructive pulmonary disease patients has not yet been established. In this study, we conducted a systematic review and meta-analysis to assess stroke risk among chronic obstructive pulmonary disease patients. PubMed, EMBASE, and the Cochrane Library were systematically searched from database inception until December 31, 2016 to identify longitudinal observational studies that investigated the association between chronic obstructive pulmonary disease and stroke. Stroke risk was quantified by overall and subgroup analyses, and a pooled hazard ratio was calculated. Study quality was evaluated using the Newcastle-Ottawa Scale. Publication bias was assessed using Begg’s rank correlation test. Eight studies met the inclusion criteria. In a random-effects model, significantly increased stroke risk was observed among chronic obstructive pulmonary disease patients (hazard ratio, 1.30; 95% confidence interval, 1.18-1.43). In subgroup analyses stratified by stroke subtype, study quality, and adjustment by socioeconomic status, the association between increased stroke risk and chronic obstructive pulmonary disease patients was robust. Statistically significant publication bias was not detected. In summary, chronic obstructive pulmonary disease was found to be associated with increased stroke risk. Additional prospective studies are required to elucidate the mechanisms underlying the increase in stroke risk and identify effective preventive interventions

Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current

We describe direct electrical measurements of microwave-frequency dynamics in individual nanomagnets that are driven by spin transfer from a DC spin-polarized current. We map out the dynamical stability diagram as a function of current and magnetic field, and we show that spin transfer can produce several different types of magnetic excitations, including small-angle precession, a more complicated large-angle motion, and a high-current state that generates little microwave signal. The large-angle mode can produce a significant emission of microwave energy, as large as 40 times the Johnson-noise background.Comment: 12 pages, 3 figure

Optical Magnetometry

Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertial-rotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.Comment: 11 pages; 4 figures; submitted to Nature Physic

Entanglement in nuclear quadrupole resonance

Entangled quantum states are an important element of quantum information techniques. We determine the requirements for states of quadrupolar nuclei with spins >1/2 to be entangled. It was shown that entanglement is achieved at low temperature by applying a magnetic field to a quadrupolar nuclei possess quadrupole moments, which interacts with the electricfield gradient produced by the charge distribution in their surroundings.Comment: 9 pages, 5 figure

Heavy Carriers and Non-Drude Optical Conductivity in MnSi

Optical properties of the weakly helimagnetic metal MnSi have been determined in the photon energy range from 2 meV to 4.5 eV using the combination of grazing incidence reflectance at 80 degrees (2 meV to 0.8 eV) and ellipsometry (0.8 to 4.5 eV). As the sample is cooled below 100 K the effective mass becomes strongly frequency dependent at low frequencies, while the scattering rate developes a linear frequency dependence. The complex optical conductivity can be described by the phenomenological relation \sigma(\omega,T) \propto (\Gamma(T)+i\omega)^{-1/2} used for cuprates and ruthenates.Comment: 5 pages, ReVTeX 4, 5 figures in eps forma

R-mode oscillations and rocket effect in rotating superfluid neutron stars. I. Formalism

We derive the hydrodynamical equations of r-mode oscillations in neutron stars in presence of a novel damping mechanism related to particle number changing processes. The change in the number densities of the various species leads to new dissipative terms in the equations which are responsible of the {\it rocket effect}. We employ a two-fluid model, with one fluid consisting of the charged components, while the second fluid consists of superfluid neutrons. We consider two different kind of r-mode oscillations, one associated with comoving displacements, and the second one associated with countermoving, out of phase, displacements.Comment: 10 page