Single particle dynamics in liquid metals

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 17, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Wouter Montfrooij.Vita.Ph. D. University of Missouri--Columbia 2009.Our understanding of the liquid (or molten) state of metals has progressed far within the past decades. Thanks to the advances in both x-ray and neutron scattering sources, it is now possible to measure the dynamics on a microscopic scale with very good statistical accuracy. The dynamics given by a single particle in a liquid metal owe to self-diffusion and cage diffusion. Presented are quasielastic neutron scattering studies of various liquid metals at low momentum transfers. The first part of this thesis is devoted to the investigation of a new (and unpredicted) contribution to the hydrodynamics of liquid metals. We present a literature review of published experiments to verify the presence of this new mode in liquid metals, followed by a possible explanation for its presence in terms of collision-induced magnetism. Next, we present a neutron scattering study at low momentum transfers using liquid gallium to verify the existence of this new contribution. The contribution turns out to be non-magnetic in origin, so another set of neutron scattering experiments is carried out, determining that the contribution should be attributed to multiple scattering processes in liquid gallium (though these same experiments suggest that this contribution is not a multiple scattering effect in liquid lead and mercury). In the last chapters of the thesis we investigate the potential effects of quantum mechanical diffraction effects on the collision between two ions. To carry out the investigation, we solved the collision between two almost classical particles using the partial wave method. We calculate the importance of this diffraction mechanism in liquid metals and present their influence on the neutron scattering cross-section when measuring the collision between two ions, given by an oscillation in the scattering cross-section.Includes bibliographical reference

Fluctuating magnetic moments in liquid metals

We reanalyze literature data on neutron scattering by liquid metals and show that there is an additional broad (in energy) quasielastic mode present that is absent in x-ray scattering. This mode cannot be accounted for by the standard coherent and incoherent scattering mechanisms. We argue that this mode indicates that nonmagnetic liquid metals possess a magnetic moment which fluctuates on a picosecond time scale. This time scale is the same as the time scale of the cage-diffusion process in which an ion rattles around in the cage formed by its neighbors. We find that these fluctuating magnetic moments are present in liquid Hg, Al, Ga, and Pb and possibly also in the alkali metals.Acknowledgment is made to the donors of the American Chemical Society Petroleum Research Fund for support of this research Grant No. ACS PRF 42615-G10 . K.S. is supported by a grant from the U.S. Department of Energy Office of Nuclear Energy, Science and Technology No. DEFG07-03ID14531 to the Midwest Nuclear Science and Engineering Consortium under the Innovations in Nuclear Infrastructure and Education program

Brief Report: Additive and Subtractive Counterfactual Reasoning of Children with High-Functioning Autism Spectrum Disorders

The development of additive (‘If only I had done…’) and subtractive (‘If only I had not done….’) counterfactual reasoning was examined in children with High Functioning Autism Spectrum Disorders (HFASD) (n = 72) and typically developing controls (n = 71), aged 6–12 years. Children were presented four stories where they could generate counterfactuals based on a given consequent (e.g., ‘you left muddy footprints in the kitchen. How could that have been prevented?’). Children with HFASD increasingly used subtractive counterfactuals as they got older, but controls showed an increase in additive counterfactuals, which may be linked to their growing adaptive and flexible skills. Children with HFASD likely develop different strategies for their counterfactual reasoning. The role of IQ and ideational fluency will be discussed

Reflexive Large-Group Evaluation for Anthropology

Traditionally, anthropology has been configured as a craft, passed down from teacher to students. Yet at NUI Maynooth, anthropology is delivered to very large and diverse classes. What are the implications of this for the learning the principles of anthropology? This project sought answers to this question by bringing together staff in the Department of Anthropology as a team that also included a graduate student researcher. We set out with the ambition of using the tools of anthropology itself to investigate the teaching and learning of anthropological principles. But we were also concerned to understand the ways in which students understood ‘evaluations’, the extant systems of module evaluation of the Department, and possible ways to introduce improved methods of two-way evaluation

Reflexive Large-Group Evaluation for Anthropology

Traditionally, anthropology has been configured as a craft, passed down from teacher to students. Yet at NUI Maynooth, anthropology is delivered to very large and diverse classes. What are the implications of this for the learning the principles of anthropology? This project sought answers to this question by bringing together staff in the Department of Anthropology as a team that also included a graduate student researcher. We set out with the ambition of using the tools of anthropology itself to investigate the teaching and learning of anthropological principles. But we were also concerned to understand the ways in which students understood ‘evaluations’, the extant systems of module evaluation of the Department, and possible ways to introduce improved methods of two-way evaluation

Prospectus, March 3, 1982

JOHNSON DISCUSSES REAGAN ECONOMY; News In Brief; College loan cuts hurting middle-income families; Meltdown reveals bonanza of useful items, treasures; What is intellectual freedom?: Your ideas can win; PC happenings…: Program focuses on language, Trouble falling asleep?, Winter playtime scheduled, Cowger discusses Indian lifestyle; Officers elected; Center offers counsel, U of I sponsors Engineering Open House, Apply for achievement award; Interested in singing? Here\u27s chance; Drama department presents; Circle K celebrates week of activities; From official tornado photographer to P.C. instructor: Donna Drysdale leads unusual life; Sugar Babies : tribute to evening of burlesque; Classifieds; U-2 good, not as good as crowd expected; \u27Personal Best\u27: Controversy arouses interest; Fifth-ranked baseball team back to face tough season Cobras Coverage sports insert pages 9-12https://spark.parkland.edu/prospectus_1982/1026/thumbnail.jp

Fluctuating magnetic moments in liquid metals

We re-analyze literature data on neutron scattering by liquid metals to show that non-magnetic liquid metals possess a magnetic moment that fluctuates on a picosecond time scale. This time scale follows the motion of the cage-diffusion process in which an ion rattles around in the cage formed by its neighbors. We find that these fluctuating magnetic moments are present in liquid Hg, Al, Ga and Pb, and possibly also in the alkali metals.Comment: 17 pages, 5 figures, submitted to PR

A Screen of FDA-Approved Drugs Identifies Inhibitors of Protein Tyrosine Phosphatase 4A3 (PTP4A3 or PRL-3)

Protein tyrosine phosphatase 4A3 (PTP4A3 or PRL-3) is highly expressed in a variety of cancers, where it promotes tumor cell migration and metastasis leading to poor prognosis. Despite its clinical significance, small molecule inhibitors of PRL-3 are lacking. Here, we screened 1443 FDA-approved drugs for their ability to inhibit the activity of the PRL phosphatase family. We identified five specific inhibitors for PRL-3 as well as one selective inhibitor of PRL-2. Additionally, we found nine drugs that broadly and significantly suppressed PRL activity. Two of these broad-spectrum PRL inhibitors, Salirasib and Candesartan, blocked PRL-3-induced migration in human embryonic kidney cells with no impact on cell viability. Both drugs prevented migration of human colorectal cancer cells in a PRL-3 dependent manner and were selective towards PRLs over other phosphatases. In silico modeling revealed that Salirasib binds a putative allosteric site near the WPD loop of PRL-3, while Candesartan binds a potentially novel targetable site adjacent to the CX5R motif. Inhibitor binding at either of these sites is predicted to trap PRL-3 in a closed conformation, preventing substrate binding and inhibiting function

The role of air plethysmography in the diagnosis of chronic venous insufficiency

AbstractPurpose: The role of air plethysmography (APG) in the diagnosis of venous disease is not well defined. We conducted this study to investigate the value of APG in the diagnosis of chronic venous insufficiency and to determine its correlation with the clinical severity of disease and the anatomic distribution of reflux. Methods: We studied 186 lower extremities with duplex scanning and venography and measured the venous volume, venous filling index (VFI), ejection fraction, and residual volume fraction with APG. Limbs were categorized according to the Society for Vascular Surgery and International Society for Cardiovascular Surgery classification of clinical severity of disease and according to the anatomic distribution of valvular incompetence. Results: Sixty-one limbs had no evidence of disease (class 0), 60 limbs had mild disease (classes 1, 2, and 3), and 65 limbs had severe disease (classes 4, 5, and 6). According to the results of duplex scanning and venography, there was no evidence of reflux in 56 limbs. Isolated superficial venous reflux occurred in 52 limbs, and perforator reflux, alone or in conjunction with superficial reflux, occurred in 30. Deep reflux, with or without superficial reflux, was found in 25 limbs. Deep and perforator reflux, with or without superficial reflux, was found in 19 limbs. The VFI had a sensitivity of 80% and 99% positive predictive value for any type of reflux. The VFI was significantly different between groups of limbs with different clinical severities of disease or different types of reflux. The incidence of deep or perforator reflux in limbs with a normal VFI value was 7%, and it was 82% in limbs with a VFI of more than 5. Among 86 limbs with VFI values not corrected with use of a thigh tourniquet, 28% did not have evidence of deep or perforator reflux, and among 15 limbs with VFI values corrected with the use of a tourniquet, 33% had perforator reflux, deep reflux, or both. All APG parameters had low positive predictive values for severe disease or ulceration. The ejection fraction and residual volume fraction did not influence the clinical severity of disease, did not discriminate between types of reflux, and in combination with the VFI did not improve the predictive value of APG. Conclusions: The VFI measured by APG is an excellent predictor of venous reflux, provides an estimate of the clinical severity of disease, and at high levels predicts deep reflux, perforator reflux, or both. Correction of an abnormal VFI with a thigh tourniquet is an unreliable predictor of the absence of deep or perforator incompetence. The predictive value of APG for severe disease or ulceration is poor. The ejection fraction and residual volume fraction, individually or in combination with the VFI, add little to the diagnostic value of APG, and their routine performance may not be clinically justified. (J Vasc Surg 1998;27:660-70.

Mechanical design and development of TES bolometer detector arrays for the Advanced ACTPol experiment

The next generation Advanced ACTPol (AdvACT) experiment is currently underway and will consist of four Transition Edge Sensor (TES) bolometer arrays, with three operating together, totaling ~5800 detectors on the sky. Building on experience gained with the ACTPol detector arrays, AdvACT will utilize various new technologies, including 150mm detector wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors includes a feedhorn array of stacked silicon wafers which form a spline profile leading to each pixel. This is then followed by a waveguide interface plate, detector wafer, back short cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured from high purity copper and then gold plated. In addition to the detector array assembly, the array package also encloses cryogenic readout electronics. We present the full mechanical design of the AdvACT high frequency (HF) detector array package along with a detailed look at the detector array stack assemblies. This experiment will also make use of extensive hardware and software previously developed for ACT, which will be modified to incorporate the new AdvACT instruments. Therefore, we discuss the integration of all AdvACT arrays with pre-existing ACTPol infrastructure.Comment: 9 pages, 5 figures, SPIE Astronomical Telescopes and Instrumentation conference proceeding