3,902 research outputs found

    Issues involved in the empirical testing of a multivariate predictive system.

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    Anomalous phase of MnP at very low field

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    Manganese phosphide MnP has been investigated for decades because of its rich magnetic phase diagram. It is well known that the MnP exhibits the ferromagnetic phase transition at \Tc=292 K and the helical magnetic phase below \TN=47 K at zero field. Recently, a novel magnetic phase transition was observed at T=282T^* = 282 K when the magnetic field is lower than 5 Oe. However, the nature of the new phase has not been illuminated yet. In order to reveal it, we performed the AC and the DC magnetization measurements for a single crystal MnP at very low field. A divergent behavior of the real and the imaginary part of the AC susceptibility and a sharp increase of the DC magnetization was observed at TT^*, indicating the magnetic phase transition at TT^*. Furthermore a peculiar temperature hysteresis was observed: namely, the magnetization depends on whether cooling sample to the temperature lower than \TN or not before the measurements. This hysteresis phenomenon suggests the complicated nature of the new phase and a strong relation between the magnetic state of the new phase and the helical structure.Comment: 4 pages, 2 figure

    Analytic structure of the S-matrix for singular quantum mechanics

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    The analytic structure of the S-matrix of singular quantum mechanics is examined within a multichannel framework, with primary focus on its dependence with respect to a parameter (Ω) that determines the boundary conditions. Specifically, a characterization is given in terms of salient mathematical and physical properties governing its behavior. These properties involve unitarity and associated current-conserving Wronskian relations, time-reversal invariance, and Blaschke factorization. The approach leads to an interpretation of effective nonunitary solutions in singular quantum mechanics and their determination from the unitary family.Fil: Camblong, Horacio E.. University of San Francisco; Estados UnidosFil: Epele, Luis Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física. Laboratorio de Física Teórica; ArgentinaFil: Fanchiotti, Huner. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física. Laboratorio de Física Teórica; ArgentinaFil: García Canal, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física. Laboratorio de Física Teórica; Argentin

    Shelfbreak jet structure and variability off New Jersey using ship of opportunity data from the CMV Oleander

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Forsyth, J., Andres, M., & Gawarkiewicz, G. . Shelfreak jet structure and variability off New Jersey using ship of opportunity data from the CMV Oleander. Journal of Geophysical Research: Oceans, 125(9), (2020): e2020JC016455. doi:10.1029/2020JC016455.Repeat measurements of velocity and temperature profiles from the Container Motor Vessel (CMV) Oleander provide an unprecedented look into the variability on the New Jersey Shelf and upper continental slope. Here 1362 acoustic Doppler current profiler (ADCP) velocity sections collected between 1994 and 2018 are analyzed in both Eulerian and stream coordinate reference frames to characterize the mean structure of the Shelfbreak Jet, as well as its seasonal to decadal variability. The Eulerian mean Shelfbreak Jet has a maximum jet velocity of 0.12 m s−1. The maximum jet velocity peaks in April and May and reaches its minimum in July and August. In a stream coordinate framework, the jet is only identified in 61% of transects, and the mean stream coordinate Shelfbreak Jet has a maximum jet velocity of 0.32 m s−1. Evidence is found that Warm Core Rings, originating from the Gulf Stream arriving in the Slope Sea adjacent to the New Jersey Shelf, shift the Shelfbreak Jet onshore of its mean position or entirely shutdown the Shelfbreak Jet's flow. At interannual timescales, variability in the Shelfbreak Jet velocity is correlated with the temperature on the New Jersey Shelf 2 months later. When considered in a stream coordinate framework, Shelfbreak Jet have decreased over the time period considered in the study.J. F. and M. A. were supported by NSF OCE‐1634094 and OCE‐1924041. G. G was supported by NSF OCE‐1851261

    The impact of Warm Core Rings on Middle Atlantic Bight shelf temperature and shelf break velocity

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Forsyth, J., Gawarkiewicz, G., & Andres, M. The impact of Warm Core Rings on Middle Atlantic Bight shelf temperature and shelf break velocity. Journal of Geophysical Research: Oceans, 127, (2022): e2021JC017759, https://doi.org/10.1029/2021jc017759.Warm Core Rings (WCRs) are known to disrupt the shelf flow as well as drive strong heat transport onto the Middle Atlantic Bight shelf. We examine 27 rings sampled by the container ship Oleander, 16 rings which have in-situ velocity data and 11 rings identified from satellite sea surface height but with in-situ temperature data, to study the variability in rings' impact on shelf break velocities and on the temperature of the adjacent shelf. WCRs that have higher rotational velocities and are closer to the shelf are found to exert greater influence on the along-shelf velocities, with the fastest and closest rings reversing the direction of flow at the shelf break. As rings approach the study site, the Shelfbreak Jet is faster than when the rings are about to exit the study site, likely due to first steepening then flattening of the isopycnals at the Shelfbreak Front. Rings also have lasting impacts on the shelf temperature: rings with faster rotational velocities cool the shelf and rings with slower rotational velocities warm the shelf. The evolution of temperature on the shelf as a ring passes is strongly tied to the season. During warmer seasons, when temperature stratification on the shelf is strong, a ring cools the shelf; during periods of weak thermal stratification, rings tend to warm the shelf. Rings which cool the shelf are additionally associated with increased upwelling as they pass the study site.J. Forsyth and M. Andres were supported by OCE-1924041. J. Forsyth and G. Gawarkiewicz were supported by ONR N00014-19-1-2646. G. Gawarkiewicz was also supported by NSF under grant OCE-1851261

    Human Mesenchymal Stem Cell Secretome Driven T Cell Immunomodulation Is IL-10 Dependent

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    Financial support was provided by the Ministry of Higher Education and Scientific Research, Iraq (S1443) and the Guy Hilton Asthma Trust.Peer reviewedPublisher PD

    Transcriptional profiling reveals altered biological characteristics of chorionic stem cells from women with gestational diabetes

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    Background Gestational diabetes (GDM) is a common complication of pregnancy. The impact of pregnancy complications on placental function suggests that extraembryonic stem cells in the placenta may also be affected during pregnancy. Neonatal tissue-derived stem cells, with the advantages of their differentiation capacity and non-invasive isolation processes, have been proposed as a promising therapeutic avenue for GDM management through potential cell therapy approaches. However, the influence of GDM on autologous stem cells remains unclear. Thus, studies that provide comprehensive understanding of stem cells isolated from women with GDM are essential to guide future clinical applications. Methods Human chorionic membrane-derived stem cells (CMSCs) were isolated from placentas of healthy and GDM pregnancies. Transcriptional profiling was performed by DNA microarray, and differentially regulated genes between GDM- and Healthy-CMSCs were used to analyse molecular functions, differentiation, and pathway enrichment. Altered genes and biological functions were validated via real-time PCR and in vitro assays. Results GDM-CMSCs displayed, vs. Healthy-CMSCs, 162 upregulated genes associated with increased migration ability, epithelial development, and growth factor-associated signal transduction while the 269 downregulated genes were strongly linked to angiogenesis and cellular metabolic processes. Notably, significantly reduced expression of detoxification enzymes belonging to the aldehyde dehydrogenase gene families (ALDH1A1/1A2, ALDH2, ALDH3) accounted for downregulation across several metabolic pathways. ALDH activity and inhibitor assays indicated that reduced gene expression of ALDHs affected ALDH enzymatic functions and resulted in oxidative stress dysregulation in GDM-CMSCs. Conclusion Our combined transcriptional analysis and in vitro functional characterisation have provided novel insights into fundamental biological differences in GDM- and Healthy-CMSCs. Enhanced mobility of GDM-CMSCs may promote MSC migration toward injured sites; however, impaired cellular metabolic activity may negatively affect any perceived benefit

    Promoted Ignition and Burning Tests of Stainless Steel in Flowing and Nonflowing Oxygen

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    The Industry-Sponsored Metals Combustion Test Program 96-1 was coordinated through Wendell Hull & Associates, Inc. on behalf of several contributing companies, and all design and testing was performed at the NASA White Sands Test Facility. Phase I of this test program studied the threshold pressure for self-sustained burning of various types and sizes of stain less steel rods in nonflowing oxygen, as observed in Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres (ASTM G 124-95). Phase II studied the ignition and propagation of burning of 316L stainless steel rods and pipe in flowing gaseous oxygen. The test sample configurations were chosen to replicate previous promoted ignition and burning tests as well as to represent geometries and cross-sectional thicknesses common in industrial piping applications. The gas pressw'es and velocities for the test matrix were selected to generally compare with CGA G-4.4 guidelines for the use of stain less steel in oxygen service. This paper summarizes the results from the Phase I nonflowing oxygen tests and presents in detail the results of the Phase II flowing oxygen tests. The maximum sample burn-length is shown as a function of test pressure in Phase 1 and also as a function of gas velocity in Phase IT. These results indicate that flowing oxygen, under the given test conditions, significantly affects maximum sample burn length as compared to nonflowing oxygen. Supplementary flowing oxygen test data on stainless steel rods from a follow-up test program are consistent with these results and are presented herein
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