14,131 research outputs found

    Norman Julius Zabusky OBITUARY

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    Norman Julius Zabusky, who laid the foundations for several critical advancements in nonlinear science and experimental mathematics, died of idiopathic pulmonary fibrosis on 5 February 2018 in Beersheba, Israel. He also made fundamental contributions to computational fluid dynamics and advocated the importance of visualization in science.Published versio

    Global Phase Space of Coherence and Entanglement in a double-well BEC

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    Ultracold atoms provide an ideal system for the realization of quantum technologies, but also for the study of fundamental physical questions such as the emergence of decoherence and classicality in quantum many-body systems. Here, we study the global structure of the quantum dynamics of bosonic atoms in a double-well trap and analyze the conditions for the generation of many-particle entanglement and spin squeezing which have important applications in quantum metrology. We show how the quantum dynamics is determined by the phase space structure of the associated mean-field system and where true quantum features arise beyond this `classical' approximation

    Spectroscopy of a synthetic trapped ion qubit

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    133Ba+^{133}\text{Ba}^+ has been identified as an attractive ion for quantum information processing due to the unique combination of its spin-1/2 nucleus and visible wavelength electronic transitions. Using a microgram source of radioactive material, we trap and laser-cool the synthetic AA = 133 radioisotope of barium II in a radio-frequency ion trap. Using the same, single trapped atom, we measure the isotope shifts and hyperfine structure of the 62P1/26^2 \text{P}_{1/2} \leftrightarrow 62S1/26^2 \text{S}_{1/2} and 62P1/26^2 \text{P}_{1/2} \leftrightarrow 52D3/25^2 \text{D}_{3/2} electronic transitions that are needed for laser cooling, state preparation, and state detection of the clock-state hyperfine and optical qubits. We also report the 62P1/26^2 \text{P}_{1/2} \leftrightarrow 52D3/25^2 \text{D}_{3/2} electronic transition isotope shift for the rare AA = 130 and 132 barium nuclides, completing the spectroscopic characterization necessary for laser cooling all long-lived barium II isotopes

    Frequency stabilization of an external-cavity diode laser

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    Using a hybrid optical/electronic technique, an external-cavity diode laser was frequency stabilized with respect to the sub-Doppler spectrum of cesium vapor. Laser linewidths of 65 kHz and frequency stabilities of ±10 kHz were obtained

    Supercritical Carbon Dioxide Extraction of Southern Pine and Ponderosa Pine

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    Pine wood and bark were extracted with supercritical (SC) carbon dioxide under various experimental conditions. The extractive yields ranged from 20-60% relative to the total diethyl ether extractive content. The yields were dependent on temperature, pressure, particle size, and fluid to wood ratio. The addition of ethanol to bark particles prior to SC CO2 extraction produced higher yields of extracts relative to extractions without the addition of ethanol. Gas chromatographic (GC) analysis of selected SC carbon dioxide extracts revealed that the concentration of resin acids, as well as the yield of pure abietic acid, increased with temperature at constant pressure. Fatty acids were more soluble in SC carbon dioxide relative to diethyl ether. The concentration of fatty acids in SC carbon dioxide extracts did not appear to follow definite trends. In addition, observation of the wood particles with scanning electron microscope (SEM) revealed that the supercritical extraction process did not appear to significantly alter the wood surface structure

    Marketing A Community: Strategic Planning and Execution

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    Allan C. Reddy is Professor in the Department of Marketing and Economics at Valdosta State College. David P. Campbell is an Assistant Professor in the Department of Marketing and Economics at Valdosta State College

    Marked expansion of exocrine and endocrine pancreas with incretin therapy in humans with increased exocrine pancreas dysplasia and the potential for glucagon-producing neuroendocrine tumors.

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    Controversy exists regarding the potential regenerative influences of incretin therapy on pancreatic β-cells versus possible adverse pancreatic proliferative effects. Examination of pancreata from age-matched organ donors with type 2 diabetes mellitus (DM) treated by incretin therapy (n = 8) or other therapy (n = 12) and nondiabetic control subjects (n = 14) reveals an ∼40% increased pancreatic mass in DM treated with incretin therapy, with both increased exocrine cell proliferation (P < 0.0001) and dysplasia (increased pancreatic intraepithelial neoplasia, P < 0.01). Pancreata in DM treated with incretin therapy were notable for α-cell hyperplasia and glucagon-expressing microadenomas (3 of 8) and a neuroendocrine tumor. β-Cell mass was reduced by ∼60% in those with DM, yet a sixfold increase was observed in incretin-treated subjects, although DM persisted. Endocrine cells costaining for insulin and glucagon were increased in DM compared with non-DM control subjects (P < 0.05) and markedly further increased by incretin therapy (P < 0.05). In conclusion, incretin therapy in humans resulted in a marked expansion of the exocrine and endocrine pancreatic compartments, the former being accompanied by increased proliferation and dysplasia and the latter by α-cell hyperplasia with the potential for evolution into neuroendocrine tumors

    Protein associated with SMAD1 (PAWS1/FAM83G) is a substrate for type I bone morphogenetic protein receptors and modulates bone morphogenetic protein signalling

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    Bone morphogenetic proteins (BMPs) control multiple cellular processes in embryos and adult tissues. BMPs signal through the activation of type I BMP receptor kinases, which then phosphorylate SMADs 1/5/8. In the canonical pathway, this triggers the association of these SMADs with SMAD4 and their translocation to the nucleus, where they regulate gene expression. BMPs can also signal independently of SMAD4, but this pathway is poorly understood. Here, we report the discovery and characterization of PAWS1/FAM83G as a novel SMAD1 interactor. PAWS1 forms a complex with SMAD1 in a SMAD4-independent manner, and BMP signalling induces the phosphorylation of PAWS1 through BMPR1A. The phosphorylation of PAWS1 in response to BMP is essential for activation of the SMAD4-independent BMP target genes NEDD9 and ASNS. Our findings identify PAWS1 as the first non-SMAD substrate for type I BMP receptor kinases and as a novel player in the BMP pathway. We also demonstrate that PAWS1 regulates the expression of several non-BMP target genes, suggesting roles for PAWS1 beyond the BMP pathway
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