A global low order spectral model designed for climate sensitivity studies

A two level, global, spectral model using pressure as a vertical coordinate is developed. The system of equations describing the model is nonlinear and quasi-geostrophic. A moisture budget is calculated in the lower layer only with moist convective adjustment between the two layers. The mechanical forcing of topography is introduced as a lower boundary vertical velocity. Solar forcing is specified assuming a daily mean zenith angle. On land and sea ice surfaces a steady state thermal energy equation is solved to calculate the surface temperature. Over the oceans the sea surface temperatures are prescribed from the climatological average of January. The model is integrated to simulate the January climate

Towards Rapid Parameter Estimation on Gravitational Waves from Compact Binaries using Interpolated Waveforms

Accurate parameter estimation of gravitational waves from coalescing compact binary sources is a key requirement for gravitational-wave astronomy. Evaluating the posterior probability density function of the binary's parameters (component masses, sky location, distance, etc.) requires computing millions of waveforms. The computational expense of parameter estimation is dominated by waveform generation and scales linearly with the waveform computational cost. Previous work showed that gravitational waveforms from non-spinning compact binary sources are amenable to a truncated singular value decomposition, which allows them to be reconstructed via interpolation at fixed computational cost. However, the accuracy requirement for parameter estimation is typically higher than for searches, so it is crucial to ascertain that interpolation does not lead to significant errors. Here we provide a proof of principle to show that interpolated waveforms can be used to recover posterior probability density functions with negligible loss in accuracy with respect to non-interpolated waveforms. This technique has the potential to significantly increase the efficiency of parameter estimation.Comment: 7 pages, 2 figure

Simulations of a Scintillator Compton Gamma Imager for Safety and Security

We are designing an all-scintillator Compton gamma imager for use in security investigations and remediation actions involving radioactive threat material. To satisfy requirements for a rugged and portable instrument, we have chosen solid scintillator for the active volumes of both the scatter and absorber detectors. Using the BEAMnrc/EGSnrc Monte Carlo simulation package, we have constructed models using four different materials for the scatter detector: LaBr_3, NaI, CaF_2 and PVT. We have compared the detector performances using angular resolution, efficiency, and image resolution. We find that while PVT provides worse performance than that of the detectors based entirely on inorganic scintillators, all of the materials investigated for the scatter detector have the potential to provide performance adequate for our purposes.Comment: Revised text and figures, Presented at SORMA West 2008, Published in IEEE Transactions on Nuclear Scienc

Correlation of ERTS multispectral imagery with suspended matter and chlorophyll in lower Chesapeake Bay

The feasibility of using multispectral satellite imagery to monitor the characteristics of estuarine waters is being investigated. Preliminary comparisons of MSS imagery with suspended matter concentrations, particle counts, chlorophyll, transmittance and bathymetry have been made. Some visual correlation of radiance with particulates and chlorophyll has been established. Effects of bathymetry are present, and their relation to transmittance and radiance is being investigated. Greatest detail in suspended matter is revealed by MSS band 5. Near-surface suspended sediment load and chlorophyll can be observed in bands 6 and 7. Images received to date have partially defined extent and location of high suspensate concentrations. Net quantity of suspended matter in the lower Bay has been decreasing since the inception of the study, and represents the diminution of turbid flood waters carried into the Bay in late September, 1972. The results so far point to the utility of MSS imagery in monitoring estuarine water character for the assessment of siltation, productivity, and water types

Radio-frequency dressing of multiple Feshbach resonances

We demonstrate and theoretically analyze the dressing of several proximate Feshbach resonances in Rb-87 using radio-frequency (rf) radiation. We present accurate measurements and characterizations of the resonances, and the dramatic changes in scattering properties that can arise through the rf dressing. Our scattering theory analysis yields quantitative agreement with the experimental data. We also present a simple interpretation of our results in terms of rf-coupled bound states interacting with the collision threshold.Comment: 4+ pages, 3 figures, 1 table; revised introduction & references to reflect published versio

Mountain glaciers of NE Asia in the near future: a projection based on climate-glacier systems' interaction

International audienceIn this study we consider contrasting continental (Orulgan, Suntar-Khayata and Chersky ranges located in the Pole of Cold area at the contact of Atlantic and Pacific influences) and maritime (Kamchatka under the Pacific influence) Russian glacier systems. Our purpose is to present a simple method for the projection of change of the main parameters of these glacier systems with climate change. To achieve this aim, we constructed vertical profiles of mass balance (accumulation and ablation) based both on meteorological observations for the mid to late 20th century and an ECHAM4 GCM scenario for 2040?2069. The observations and scenario were used for defining the recent and future equilibrium line altitude (ELA) for each glacier system. The altitudinal distributions of the areas covered with glacier ice were determined for present and future states of the glacier systems, taking into account the correlation of the change of the ELA and glacier-termini levels. We also give estimates of the possible changes of the areas and morphological structure of North-eastern Asia glacier systems and their mass balance characteristics from the ECHAM4 scenario. Finally, we compare characteristics of the continental and maritime glacier systems stability under conditions of global warming

Mexiletine (NaMuscla) for the treatment of myotonia in non-dystrophic myotonic disorders

Introduction: NaMuscla, (mexiletine), is the first licensed treatment for the Non-Dystrophic Myotonias (NDM). NDM are categorized by genetic ion channel dysfunction and cause significant morbidity. To date, off-license mexiletine, although less costly, has sometimes been subject to breaches in supply causing significant regional and national variation in availability. Areas covered: The evidence supporting mexiletine use in NDM, its mechanism of action, chemistry, and pharmacodynamics is reviewed. The evidence for other, unlicensed medications, used to treat myotonia as well as new antimyotonic compounds in development is also reviewed. Expert opinion: Mexiletine is an effective and safe treatment for NDM. However, while mexiletine is very effective in reducing muscle stiffness, it is less effective at treating the pain associated with NDM and some SCN4A genotypes may not respond to mexiletine treatment. In addition, gastrointestinal discomfort is frequent and may prevent adequate dose titration. Since the designation of mexiletine as an orphan drug for NDM, level 1 evidence for the antimyotonic effect of lamotrigine has emerged. However, no superiority trials have been completed. A head-to-head trial to compare the efficacy of mexiletine and lamotrigine in reducing both muscle stiffness and pain and to determine variation in genotype response would facilitate greater precision medicine in NDM

Correlation of chlorophyll, suspended matter, and related parameters of waters in the lower Chesapeake Bay area to LANDSAT-1 imagery

The author has identified the following significant results. An effort to relate water parameters of the lower Chesapeake Bay area to multispectral scanner images of LANDSAT 1 has shown that some spectral bands can be correlated to water parameters, and has demonstrated the feasibility of synoptic mapping of estuaries by satellite. Bands 5 and 6 were shown to be useful for monitoring total particles. Band 5 showed high correlation with suspended sediment concentration. Attenuation coefficients monitored continuously by ship along three baselines were cross correlated with radiance values on three days. Improved correlations resulted when tidal conditions were taken into consideration. A contouring program was developed to display sediment variation in the lower Chesapeake Bay from the MSS bands