Physical Sciences and Mathematics Commons^™

New Isotopic Evidence For Chronic Lead Contamination In The San Francisco Bay Estuary System: Implications For The Persistence Of Past Industrial Lead Emissions In The Biosphere, Douglas J. Steding, Charles E. Dunlap, A. Russell Flegal

Charles Dunlap

Measurements of lead isotope compositions in unfiltered San Francisco Bay waters from 1989 to 1998 have brought new insights into the cycling of anthropogenic lead in estuaries. Isotopic com- positions of lead in the shallow (<2 m) southern reach were essentially invariant (~90% derived from 1960s–1970s leaded gasoline) during the study period because of limited hydraulic flushing and the remobilization of lead from bottom sediments. In contrast, in the northern reach freshwater flushing from the San Joaquin and Sacramento rivers produced seasonal and decadal variations in lead isotope compositions. The seasonal shifts are attributed to advection of soils containing late 1980s gasoline lead into the bay during winter rains. Mass balance calculations indicate that only a small fraction (1–10%) of this leaded gasoline fallout from the late 1980s has been washed out of the San Joaquin and Sacramento rivers’ drainage basin by 1995. Superimposed on this seasonal cycling was a long-term systematic shift in the component of gasoline lead expressed in the river systems, with a small (~5–10%) decrease in the amount of 1960s–1970s gasoline lead in river and North Bay waters. The retention of gasoline lead in the river systems draining into the bay as well as San Francisco Bay sediments indicates that historic gasoline deposits may remain in the combined riparian/estuarine system for decades. Such a persistence is in contraindication to recent reports of rapid (annual) decreases in lead contamination in other environments, and the link between climate and contaminant transport suggests local or global climate change will have an impact on contaminant distribution and fate.

Past Leaded Gasoline Emissions As A Nonpoint Source Tracer In Riparian Systems: A Study Of River Inputs To San Francisco Bay, Charles E. Dunlap, Robin Bouse, A. Russell Flegal

Charles Dunlap

Variations in the isotopic composition of lead in 1995- 1998 river waters flowing into San Francisco Bay trace the washout of lead deposited in the drainage basin from leaded gasoline combustion. At the confluence of the Sacramento and San Joaquin rivers where they enter the Bay, the isotopic compositions of lead in the waters define a linear trend away from the measured historical compositions of leaded gas in California. The river waters are shifted away from leaded gasoline values and toward an isotopic composition similar to Sierra Nevadan inputs which became the predominant source of sedimentation in San Francisco Bay …

The Neural Basis Of Strategy And Skill In Sentence-Picture Verification, Erik D. Reichle, Patricia A. A. Carpenter, Marcel Adam Just

Marcel Adam Just

No abstract provided.

The Discovery-Oriented Approach To Organic Chemistry. 3. Boron-Trifluoride Catalyzed Rearrangement Of Cis- And Trans-Stilbene Oxides. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram S. Mohan, Erik A. Sgariglia, Regina Schopp, Kostas Gavardinas

Ram S. Mohan

Isolation Of Curcumin From Tumeric, Ram S. Mohan, Andrew M. Anderson, Matthew S. Mitchell

Ram S. Mohan

No abstract provided.

Bismuth(Iii) Oxide Perchlorate Promoted Rearrangement Of Epoxides To Aldehydes And Ketones, Ram S. Mohan, Andrew M. Anderson, Jesse M. Blazek, Parie Garg, Brian J. Payne

Ram S. Mohan

Trajectory Mapping: A Tool For Validation Of Trace Gas Observations, Gary A. Morris, James F. Gleason, Jerald Ziemke, Mark R. Schoeberl

Gary A. Morris

We investigate the effectiveness of trajectory mapping(TM) as a data validation tool. TM combines a dynamical model of the atmosphere with trace gas observations to provide more statistically robust estimates of instrument performance over much broader geographic areas than traditional techniques are able to provide. We present four detailed case studies selected so that the traditional techniques are expected to work well. In each case the TM results are equivalent to or improve upon the measurement comparisons performed with traditional approaches. The TM results are statistically more robust than those achieved using traditional approaches since the TM comparisons occur over …

Configurational Entropy And Diffusivity Of Supercooled Water, Francis W. Starr, A. Scala, E. La Nave, F. Sciortino, H. E. Stanley

Francis Starr

No abstract provided.

Semiparametric Regression: An Exposition And Application To Print Advertising Data, Michael S. Smith, Robert Kohn, Sharat K. Mathur

Michael Stanley Smith

A new regression based approach is proposed for modeling marketing databases. The approach is Bayesian and provides a number of significant improvements over current methods. Independent variables can enter into the model in either a parametric or nonparametric manner, significant variables can be identified from a large number of potential regressors and an appropriate transformation of the dependent variable can be automatically selected from a discrete set of pre-specified candidate transformations. All these features are estimated simultaneously and automatically using a Bayesian hierarchical model coupled with a Gibbs sampling scheme. Being Bayesian, it is straightforward to introduce subjective information about …

Working Memory And Executive Function: Evidence From Neuroimaging, Patricia A. Carpenter, Marcel Adam Just, Erik D. Reichle

Marcel Adam Just

No abstract provided.

Reflexive Autopoietic Systems Theory, Kent D. Palmer

Kent D. Palmer

Exploring the Meta-systems of Emergent Worlds

Wolf-Rayet Wind Structure And Optical Variability., Q. Li, J. C. Brown, R. Ignace, J. P. Cassinelli, L. M. Oskinova

Richard Ignace

Results are presented on the expected variability of Wolf-Rayet (WR) stars in broad-band optical polarimetry and photometry, and in emission line profiles, due to an inhomogeneous random distribution of blobs in spherical geometry. Time dependent 3-D simulations are carried out with blob ejection random in time and direction, and the radiation properties are evaluated in the optically thin limit. In contrast with previous purely statistical analyses, inclusion in the present treatment of a beta velocity law and stellar occultation effects can yield results consistent with observations of the mean polarisation bar p and the ratio R=sigma_p /sigma_phot of polarimetric to …

Adaptive Testing In Arch Models, Douglas G. Steigerwald, Oliver Linton

Douglas G. Steigerwald

Specification tests for conditional heteroskedasticity that are derived under the assumption that the density of the innovation is Gaussian may not be powerful in light of the recent empirical results that the density is not Gaussian. We obtain specification tests for conditional heteroskedasticity under the assumption that the innovation density is a member of a general family of densities. Our test statistics maximize asymptotic local power and weighted average power criteria for the general family of densities. We establish both first-order and second-order theory for our procedures. Simulations indicate that asymptotic power gains are achievable in finite samples.

An Elliptic Equation With Spike Solutions Concentrating At Local Minima Of The Laplacian Of The Potential, Gregory S. Spradlin

Gregory S. Spradlin

Internal Waves Revealed By Synthetic Aperture Radar (Sar) Imagery In The Vicinity Of The Eastern Cretan Arc Straits (Eastern Mediterranean), Adonis Velegrakis, E. Oikonomou, A. Theocharis, M Collins, H Kontoyannis, V Papadopoulos, George Voulgaris, T. Wells, E. Balopoulos

George Voulgaris

Internal waves have been detected on ERS-1 SAR images obtained during late summer over the eastern Cretan Straits, an area characterised by complex regional physiography, bottom topography, flow regime and stratification patterns of the upper part of the water column. Analysis of the imaged characteristics of the internal waves has revealed a strong diversity in form, propagation direction and type of sea surface modulation, which indicates various mechanisms of generation. Analysis of the currents recorded over the area shows that, although semi-diurnal tidal currents are present, these are of low magnitude in comparison with the overall flow and, therefore, tidal …

Rule-Mitigated Collaboration Technology, Carl Chang, Alexei Vorontsov, Jia Zhang, Francis Quek

Jia Zhang

No abstract provided.

Accelerated Assessment And Selection Of Design Concepts In The Presence Of Qualitative Uncertainty And Imprecision, D. Verma, Caroline Lubert, W. Fabrycky

Caroline P Lubert

No abstract provided.

Fuzzy Neural Network Models For Supervised Classification: Multispectral Image Analysis, Arun D. Kulkarni, Kamlesh Lulla

Arun Kulkarni

No abstract provided.

A Perturbation Of A Periodic Hamiltonian System, Gregory S. Spradlin

Gregory S. Spradlin

No abstract provided.

Phase Imaging: Deep Or Superficial?, Nancy Burnham, O Behrend, L Odoni, J Loubet

Nancy A. Burnham

Phase images acquired while intermittently contacting a sample surface with the tip of an atomic force microscope cantilever are not easy to relate to material properties. We have simulated dynamic force curves and compared simulated with experimental results. For some cantilever–sample combinations, the interaction remains a surface effect, whereas for others, the tip penetrates the sample significantly. Height artifacts in the “topography” images, and the role of the sample stiffness, work of adhesion, damping, and topography in the cantilever response manifest themselves to different extents depending on the indentation depth.

Transparent Stacked Organic Light Emitting Devices. I. Design Principles And Transparent Compound Electrodes, G. Gu, G. Parthasarathy, P. E. Burrows, Peifang Tian, I. G. Hill, A. Kahn, S. R. Forrest

Peifang Tian

Vertical stacking of organic light emitting devices (OLEDs) that emit the three primary colors is a means for achieving full-color flat panel displays. The physics, performance, and applications of stacked OLEDs (SOLEDs) are discussed in this and the following paper (Papers I and II, respectively). In Paper I, we analyze optical microcavity effects that can distort the emission colors of SOLEDs if not properly controlled, and describe design principles to minimize these parasitic effects. We also describe the fabrication and operating characteristics of transparent contacts that are an integral part of SOLEDs. We demonstrate that both metal-containing and metal-free transparent …

Transparent Stacked Organic Light Emitting Devices. Ii. Device Performance And Applications To Displays, G. Gu, G. Parthasarathy, Peifang Tian

Peifang Tian

Vertical stacking of organic light emitting devices (OLEDs) that emit the three primary colors is shown to be a means for achieving efficient and bright full-color displays. In Paper I, we addressed stacked OLED (SOLED) design and fabrication principles to optimize emission colors, operating voltage, and efficiency. Here, we present results on two different (metal-containing and metal-free cathode) SOLED structures that exhibit performance suitable for many full-color display applications. The operating voltages at 10 mA/cm2 (corresponding to video display brightnesses) are 6.8, 8.5, and 12.1 V for the red (R), green (G), and blue (B) elements of the metal-containing SOLED, …

Development And Student Use Of Web-Based Prelabs In Analytical Chemistry Courses, Mark Anderson, Brian Tissue

Mark R. Anderson

No abstract is currently available.

Illuminesse :Possible Side Effects & Benefits, Marlenehull Marlenehull

marlenehull marlenehull

Regional Hydrology Of The Dixie Valley Geothermal Field, Nevada: Preliminary Interpretations Of Chemical And Isotopic Data, Gregory Nimz, Cathy Janik, Fraser Goff, Charles Dunlap, Mark Huebner, Dale Counce, Stuart Johnson

Charles Dunlap

Chemical and isotopic analyses of Dixie Valley regional waters indicate several distinct groups ranging in recharge age from Pleistocene (<20 ka) to recent (<50a). Valley groundwater is older than water from perennial springs and artesian wells in adjacent ranges, with Clan Alpine range (east) much younger (most <50a) than Stillwater range (west; most > 1OOOa).Geothermal field fluids (-12-14 ka) appear derived from water similar in composition to non-thermal groundwater observed today in valley artesian wells (also -14 ka). Geothermal fluid interaction with mafic rocks (Humboldt Lopolith) appears to be common, and significant reaction with granodiorite may also occur. Despite widespread occurrence of carbonate rocks, largescale chemical interaction appears minor. Age asymmetry of the ranges, more extensive interaction with deep- seated waters in the west, and distribution of springs and artesian wells suggest the existence …

Glueball Production In Peripheral Heavy-Ion Collisions, Alec Schramm

Alec J Schramm

The method of equivalent quanta is applied both to photon-photon and, by analogy, to double pomeron exchange in heavy-ion collisions. This Weizsäcker-Williams approach is used to calculate production cross sections for the glueball candidate fJ(1710) meson via photon-photon and pomeron-pomeron fusion in peripheral heavy-ion collisions at both RHIC and LHC energies. The impact parameter dependence for total and elastic cross sections is presented, and compared with results for proton-proton collisions.

Precise, Scalable Shadow Mask Patterning Of Vacuum-Deposited Organic Light Emitting Devices, Peifang Tian, V. Bulovic, P. Burrows, G. Gu, S. Forrest, T. Zhou

Peifang Tian

We demonstrate a scheme to pattern vacuum-deposited, small molecular weight organic light emitting diodes 􏰉OLEDs􏰀. Both the organic thin films and the metallic electrodes are patterned by shifting the position of a single shadow mask which accompanies the substrate throughout the deposition process. A full color, stacked OLED 􏰉SOLED􏰀 has been fabricated using this technique. The substrate movement relative to the mask was manually controlled to a root mean square accuracy of 􏰑8 􏰇m using a mask translating fixture. The performance of the patterned SOLED is comparable with that of devices fabricated by conventional, low tolerance methods. The limits to …

Computational Complexity For Continuous Time Dynamics, Hava Siegelmann, Asa Ben-Hur, Shmuel Fishman

Hava Siegelmann

Dissipative flows model a large variety of physical systems. In this Letter the evolution of such systems is interpreted as a process of computation; the attractor of the dynamics represents the output. A framework for an algorithmic analysis of dissipative flows is presented, enabling the comparison of the performance of discrete and continuous time analog computation models. A simple algorithm for finding the maximum of n numbers is analyzed, and shown to be highly efficient. The notion of tractable (polynomial) computation in the Turing model is conjectured to correspond to computation with tractable (analytically solvable) dynamical systems having polynomial complexity.

Back To Basics – Statistics For Logisticians, Caroline Lubert

Caroline P Lubert

No abstract provided.

The Discovery-Oriented Approach To Organic Chemistry. 2. Selectivity In Alcohol Oxidation. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram S. Mohan, Steven R. Shadwick

Ram S. Mohan