2,549 research outputs found
Nucleonic coal detector with independent, hydropneumatic suspension
The design of a nucleonic, coal interface detector which measures the depth of coal on the roof and floor of a coal mine is presented. The nucleonic source and the nucleonic detector are on independent hydropneumatic suspensions to reduce the measurement errors due to air gap
Contradictory Origins and Racializing Legacy of the 1968 Bilingual Education Act: Urban Schooling, Anti-Blackness, and Oakland’s 1996 Black English Language Education Policy
Extension of a Spectral Bounding Method to Complex Rotated Hamiltonians, with Application to
We show that a recently developed method for generating bounds for the
discrete energy states of the non-hermitian potential (Handy 2001) is
applicable to complex rotated versions of the Hamiltonian. This has important
implications for extension of the method in the analysis of resonant states,
Regge poles, and general bound states in the complex plane (Bender and
Boettcher (1998)).Comment: Submitted to J. Phys.
Generating Converging Bounds to the (Complex) Discrete States of the Hamiltonian
The Eigenvalue Moment Method (EMM), Handy (2001), Handy and Wang (2001)) is
applied to the Hamiltonian, enabling
the algebraic/numerical generation of converging bounds to the complex energies
of the states, as argued (through asymptotic methods) by Delabaere and
Trinh (J. Phys. A: Math. Gen. {\bf 33} 8771 (2000)).Comment: Submitted to J. Phys.
C_8H_8: a density functional theory study of molecular geometries introducing the localised bond density
In this paper we use density functional theory with all the common exchange-correlation functionals to investigate the structures of three isomers of C_8H_8 found in F. A. Cotton's text, barrelene, cyclooctatetraene, tetramethylenecyclobutane and also ethane and ethene. All calculations were performed with TZ2P basis sets and large quadrature. The results are compared with experiment and those obtained with Hartree–Fock theory. Delocalisation in the three molecules is discussed. A localised bond density in introduced to explain the transferability of the trends in the predictions of the functionals between different molecules. Three-parameter adiabatic connection functionals are examined and their usefulness in geometry prediction questioned. Finally a physical picture of the correlation as modelled by density functional theory is presented and used to explain trends in the overestimation or underestimation of bond lengths
The acute toxicity of thallium to freshwater organisms: Implications for risk assessment.
The acute toxicity of Tl(I) to the microalga, Pseudokirchneriella subcapitata, the planktonic crustaceans, Daphnia magna and Daphnia pulex, and early-life stage of the zebrafish, Danio rerio, has been studied according to OECD protocols. Toxicological end-point concentrations for the microalga ranged from 17 μg l(-1) for a 72 h EyC25 (yield inhibition) to 80 μg l(-1) for a 72 h ErC50 (growth inhibition). Daphnia were less sensitive to Tl, with 48 h EC50s of about 1000 μg l(-1) and 1200 μg l(-1) for D. magna and D. pulex, respectively; however, end-point concentrations were reduced considerably (to about 510 μg l(-1) and 730 μg l(-1), respectively) when experiments were repeated in dechlorinated Plymouth tap water (rather than OECD medium). The 96 h LC50 for D. rerio was 870 μg l(-1) but a variety of sub-lethal effects, including enlargement of yolk sac and reduction in heart beat rate, were observed when larvae were exposed to lower concentrations. Based on these results, a predicted no effect concentration (PNEC) for Tl in freshwaters of 0.087 μg l(-1) is proposed. The PNEC is an order of magnitude lower than the only (Canadian) water quality guideline for Tl that appears to exist, and is lower than Tl concentrations reported in freshwaters impacted by historical or contemporary metal mining. Our results are also consistent with previous studies that employ different organisms and end-points in that Tl toxicity is dependent on the concentration of K+, the biogeochemical analogue of Tl+. Accordingly, regulation of Tl in the freshwater environment should factor in the relative abundance of K
David, Mickey Mouse, and the Evolution of an Icon
Abstract The transformation of an entertaining roguish figure to an institutional icon is investigated with respect to the figures of Mickey Mouse and the biblical King David. Using the three-stage evolution proposed by R. Brockway, the figures of Mickey and David are shown to pass through an initial entertaining phase, a period of model behavior, and a stage as icon. The biblical context for these shifts is basically irretrievable so the extensive materials available for changes in the Mouse provide sufficient information on personnel and social forces to both illuminate our lack of understanding for changes in David while providing some comparative material for similar development
Miniatur Loading Arm Dock-3 PT Badak NGL Bontang Dengan Sistem Emergency Shut Down (ESD)
Loading Arms in PT Badak NGL are used to distribute natural gas for shipping. The position of the ship cannot be fixed due to the wind, sea wave, stream flow, etc. If the distance is out of tolerance limit, then the Emergency Shut Down (ESD) system will be activated. ESD will release the part that is connected to the ship so that the whole distribution pipe is safe. The loading arms are controlled via Programmable Logic Controller (PLC) manually. The miniature of the loading arms is useful to train the new employees to operate them well. It is build with 1:10 ratio and controlled by PLC OMRON C200 HG. Several DC motors are used to move the arms while potentiometers are used as position sensors. The PLC will monitor whether the position is within tolerance limit or not. From the experiments, the ESD can be implemented with 16.48s for slewing motion and 16.5s for extension motion
Correlation potentials and functionals in Hartree-Fock-Kohn-Sham theory
We compute molecular Hartree-Fock-Kohn-Sham correlation potentials from ab initiocoupled-cluster densities via a modified Zhao, Morrison and Parr [Phys. Rev. A, 50, (1994) 2138] scheme involving exact exchange. We examine the potential for several small systems, and observe complex structure. By fitting a functional expansion to our potentials we obtain a closed-shell functional which is an improvement over other pure correlationfunctionals in Hartree-Fock-Kohn-Sham calculations. The leading term in our functional is dependent on the number of electrons. Our results lead us to question the utility of correlation defined within the Hartree-Fock-Kohn-Sham scheme, and to consider alternative partitionings of the exchange-correlation energy
Aberrant STYK1 expression in ovarian cancer tissues and cell lines
<p>Abstract</p> <p>Background</p> <p>Overexpression of <it>STYK1</it>, a putative serine/threonine and tyrosine receptor protein kinase has been shown to confer tumorigenicity and metastatic potential to normal cells injected into nude mice. Mutation of a tyrosine residue in the catalytic STYK1 domain attenuates the tumorigenic potential of tumor cells <it>in vivo</it>, collectively, suggesting an oncogenic role for STYK1.</p> <p>Methods</p> <p>To investigate the role of STYK1 expression in ovarian cancer, a panel of normal, benign, and ovarian cancer tissues was evaluated for STYK1 immunoreactivity using STYK1 antibodies. In addition, mRNA levels were measured by reverse transcription PCR and real-time PCR of estrogen receptors, GPR30 and STYK1 following treatment of ovarian cell lines with estrogen or G1, a GPR30 agonist, as well as western analysis.</p> <p>Results</p> <p>Our data showed higher expression of STYK1 in cancer tissues versus normal or benign. Only normal or benign, and one cancer tissue were STYK1-negative. Moreover, benign and ovarian cancer cell lines expressed <it>STYK1 </it>as determined by RT-PCR. Estradiol treatment of these cells resulted in up- and down-regulation of <it>STYK1 </it>despite estrogen receptor status; whereas G-1, a GPR30-specific agonist, increased STYK1 mRNA levels higher than that of estradiol.</p> <p>Conclusion</p> <p>We conclude that <it>STYK1 </it>is expressed in ovarian cancer and is regulated by estrogen through a GPR30 hormone-signaling pathway, to the exclusion of estrogen receptor-alpha.</p
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