Laser spectroscopy of muonic deuterium.

The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ(-).

Proton structure from the measurement of 2S-2P transition frequencies of muonic hydrogen.

Accurate knowledge of the charge and Zemach radii of the proton is essential, not only for understanding its structure but also as input for tests of bound-state quantum electrodynamics and its predictions for the energy levels of hydrogen. These radii may be extracted from the laser spectroscopy of muonic hydrogen (μp, that is, a proton orbited by a muon). We measured the 2S(1/2)(F=0)-2P(3/2)(F=1) transition frequency in μp to be 54611.

Clogging in subsurface-flow treatment wetlands: measurement, modeling and management.

This paper reviews the state of the art in measuring, modeling, and managing clogging in subsurface-flow treatment wetlands. Methods for measuring in situ hydraulic conductivity in treatment wetlands are now available, which provide valuable insight into assessing and evaluating the extent of clogging. These results, paired with the information from more traditional approaches (e.

Analysis of clogging in constructed wetlands using magnetic resonance.

In this work we demonstrate the potential of permanent magnet based magnetic resonance sensors to monitor and assess the extent of pore clogging in water filtration systems. The performance of the sensor was tested on artificially clogged gravel substrates and on gravel bed samples from constructed wetlands used to treat wastewater. Data indicate that the spin lattice relaxation time is linearly related to the hydraulic conductivity in such systems.

The size of the proton.

The proton is the primary building block of the visible Universe, but many of its properties-such as its charge radius and its anomalous magnetic moment-are not well understood. The root-mean-square charge radius, r(p), has been determined with an accuracy of 2 per cent (at best) by electron-proton scattering experiments. The present most accurate value of r(p) (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants.

Stark shift of the Cs clock transition frequency: a new experimental approach.

The blackbody radiation shift, a manifestation of the Stark effect caused by blackbody radiation, contributes to the systematic uncertainty in Cs-based frequency standards at a level of 1 x 10(-15). Few measurements of the third-order scalar electric polarizability of the Cs ground states, mainly responsible for the ac Stark shift in atomic clocks, have given better than 10% accuracy. We report progress in the development of a fully optical Ramsey pump-probe measurement in a thermal atomic beam, based on coherent population trapping (CPT), for the measurement of the third-order scalar and tensor polarizabilities of the Cs ground states.

Evaluation of a first seizure.

Seizure is a common presentation in the emergency care setting, and new-onset epilepsy is the most common cause of unprovoked seizures. The patient history and physical examination should direct the type and timing of laboratory and imaging studies. No single sign, symptom, or test dearly differentiates a seizure from a nonseizure event (e.

Alexander's disease in a neurologically normal child: a case report.

We report the clinical and MRI findings of symmetric hyperintensity involving the deep and subcortical white matter of the frontal lobes in a neurologically normal child with macrocephaly. In this patient, a serum test for mutations in glial fibrillary acidic protein, used to diagnose Alexander's disease (AD), was positive. This case indicates an extraordinarily mild or early form of juvenile-onset AD.