Role of sediments in eutrophication—A preliminary study

The report is divided into two parts. The first part contains the results of an extensive literature survey concerning the distribution of nutrients in waters and sediments and mechanisms for describing the mobility of phosphate nutrients in aquatic systems. The horizontal and vertical distribution of nutrients for Great Lakes waters in other U.S. as well as foreign lakes and rivers are presented. Phosphate nutrient mobility mechanisms are organized in a single table based upon two types of transformations: special and chemical. Twenty-four possible types of transformation categories are employed based upon the organic or inorganic form of the phosphate itself and the organic or inorganic type of spatial domain in which the phosphate is located. In the second part a laboratory technique to aid in the study of the hydrodynamic transport of phosphates in saturated soils is described. The technique is based upon a modification of the one dimensional consolidation test and employs radionucleid tracers. Typical test results are presented, though the complete study of the phenomenon is the subject of a subsequent project in progress.U.S. Department of the InteriorU.S. Geological SurveyOpe

Nutrient transport by sediment-water interaction

This report presents the results of a series of laboratory tests to investigate phosphate transport in sediments subjected to one dimensional consolidation type loading. P-32 techniques are employed. The results indicate that measurable transport occurs for phosphate concentrations on the order of 2 mg p/gm dry soil or more and for loads in excess of the preconsolidation load for the samples. In addition, the report discusses models for the exchange of phosphates between sediment or soil in lakes and lake waters. These models are expressed in a form that allows them to be used to predict the environmental impact of construction operations in aquatic environments. Three modes of interaction are discussed: 1 ) exchange due to new soil surfaces being exposed, 2) exchange due to the dispersion of soil particles in the water, and 3) release due to forced drainage of water from sediments. The conditions under which each mechanism might be influential are discussed and mathematical models are developed for quantitative predictions.U.S. Department of the InteriorU.S. Geological SurveyOpe

Polaritons and Pairing Phenomena in Bose--Hubbard Mixtures

Motivated by recent experiments on cold atomic gases in ultra high finesse optical cavities, we consider the problem of a two-band Bose--Hubbard model coupled to quantum light. Photoexcitation promotes carriers between the bands and we study the non-trivial interplay between Mott insulating behavior and superfluidity. The model displays a global U(1) X U(1) symmetry which supports the coexistence of Mott insulating and superfluid phases, and yields a rich phase diagram with multicritical points. This symmetry property is shared by several other problems of current experimental interest, including two-component Bose gases in optical lattices, and the bosonic BEC-BCS crossover problem for atom-molecule mixtures induced by a Feshbach resonance. We corroborate our findings by numerical simulations.Comment: 4 pages, 3 figure

Titanoclinohumite: A possible mineralogical site for water in the upper mantle

Titanium-rich clinohumite and layered structure minerals are observed in kimberlite and as inclusions in pyropic garnets from the Moses Rock dike, a kimberlite-bearing breccia dike in San Juan County, Utah. Associated clinopyroxenes observed as inclusions within similar pyropes and also in kimberlite are estimated to have equilibrated at depths ranging from about 50 to 150 km at modest temperatures, generally less than 1000°C. The presence of titanoclinohumite, a high-density hydrous phase, is of considerable interest as a possible site for volatiles in the earth's upper mantle. The dehydration of hydrous phases such as titanoclinohumite within the upper mantle (1) may provide water as a free phase, (2) could be important in the genesis of kimberlite and alkali-basalt magma, and (3) may be one means of producing a low-velocity zone in the upper mantle

Bose--Hubbard Models Coupled to Cavity Light Fields

Recent experiments on strongly coupled cavity quantum electrodynamics present new directions in "matter-light" systems. Following on from our previous work [Phys. Rev. Lett. 102, 135301 (2009)] we investigate Bose-Hubbard models coupled to a cavity light field. We discuss the emergence of photoexcitations or "polaritons" within the Mott phase, and obtain the complete variational phase diagram. Exploiting connections to the super-radiance transition in the Dicke model we discuss the nature of polariton condensation within this novel state. Incorporating the effects of carrier superfluidity, we identify a first-order transition between the superradiant Mott phase and the single component atomic superfluid. The overall predictions of mean field theory are in excellent agreement with exact diagonalization and we provide details of superfluid fractions, density fluctuations, and finite size effects. We highlight connections to recent work on coupled cavity arrays.Comment: 16 pages, 17 figure

Cardiac output during CPR: a comparison of two methods

Simultaneous Fick and saline dilution methods were compared for measuring cardiac output during experimental cardiac arrest and resuscitation in anesthetized dogs. During cardiopulmonary resuscitation (CPR) cardiac output averaged 53 ± 30 ml/min-kg (42% of pre-arrest values). Values obtained using the Fick vs. saline methods were highly correlated (r = 0.96), and were not statistically different (t = 1.47, df = 16)