167 research outputs found

    Structural and Magnetic Characterization of Large Area, Free-Standing Thin Films of Magnetic Ion Intercalated Dichalcogenides Mn0.25TaS2 and Fe0.25TaS2

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    Free-standing thin films of magnetic ion intercalated transition metal dichalcogenides are produced using ultramicrotoming techniques. Films of thicknesses ranging from 30nm to 250nm were achieved and characterized using transmission electron diffraction and X-ray magnetic circular dichroism. Diffraction measurements visualize the long range crystallographic ordering of the intercalated ions, while the dichroism measurements directly assess the orbital contributions to the total magnetic moment. We thus verify the unquenched orbital moment in Fe0.25TaS2 and measure the fully quenched orbital contribution in Mn0.25TaS2. Such films can be used in a wide variety of ultrafast X-ray and electron techniques that benefit from transmission geometries, and allow measurements of ultrafast structural, electronic, and magnetization dynamics in space and time

    Acceptance of COVID-19 Vaccine Among Unvaccinated Filipinos

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    Background: Access to COVID-19 vaccines was one of the global measures for containing the COVID-19 pandemic. However, it is still not known whether Filipinos accept it.  Methods: Cross-sectional study based on a modified version of the community COVID-19 vaccine acceptance survey, disseminated and collected through Google Forms to Filipinos within the Philippines aged 18-65 years old. Multinomial logistic regression analysis was performed to determine the association between the willingness to be vaccinated and sociodemographic characteristics using odds ratios (OR) with 95% confidence intervals (95%CI).  Results: Among the 1,011 participants, 79.5% were willing to accept the COVID-19 vaccine. Significant determinants (p<0.05) were age, region of residence, sex, profession, income, religion, practice of alternative medicine, and previous contact with COVID-19 positive individuals. Essential healthcare workers (OR=11.0, 95%CI=1.3-93.5), practiced alternative medicine (OR=2.4, 95%CI=1.3-4.4), with previous contact with a COVID-19 positive person (OR=2.9, 95%CI=1.4-6.0), and females>males (OR=0.6, 95%CI=.3-1.0) were also more likely to accept COVID-19 vaccination. 63.7% preferred Pfizer the most, and 54.4% preferred Sinovac the least. In contrast, married individuals, essential non-healthcare workers and private/self-employed sectors were less likely to accept COVID-19 vaccines. Many individuals who refused to be vaccinated were unsure of its safety (59.70%) and had no trust in vaccines (56.50%). Conclusion: Despite a high prevalence of acceptance of the COVID-19 vaccine in our study, there were significant sociodemographic disproportions in vaccine acceptance. Better policies urging Filipinos to get vaccinated and more effective dissemination of unified information regarding vaccines from verified sources are recommended to boost vaccine confidence in the Philippines

    Correlation energy of an electron gas in strong magnetic fields at high densities

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    The high-density electron gas in a strong magnetic field B and at zero temperature is investigated. The quantum strong-field limit is considered in which only the lowest Landau level is occupied. It is shown that the perturbation series of the ground-state energy can be represented in analogy to the Gell-Mann Brueckner expression of the ground-state energy of the field-free electron gas. The role of the expansion parameter is taken by r_B= (2/3 \pi^2) (B/m^2) (\hbar r_s /e)^3 instead of the field-free Gell-Mann Brueckner parameter r_s. The perturbation series is given exactly up to o(r_B) for the case of a small filling factor for the lowest Landau level.Comment: 10 pages, Accepted for publication in Phys.Rev.

    Standardized Measures of Coastal Wetland Condition: Implementation at a Laurentian Great Lakes Basin-Wide Scale

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    Since European settlement, over 50 % of coastal wetlands have been lost in the Laurentian Great Lakes basin, causing growing concern and increased monitoring by government agencies. For over a decade, monitoring efforts have focused on the development of regional and organism-specific measures. To facilitate collaboration and information sharing between public, private, and government agencies throughout the Great Lakes basin, we developed standardized methods and indicators used for assessing wetland condition. Using an ecosystem approach and a stratified random site selection process, birds, anurans, fish, macroinvertebrates, vegetation, and physico-chemical conditions were sampled in coastal wetlands of all five Great Lakes including sites from the United States and Canada. Our primary objective was to implement a standardized basin-wide coastal wetland monitoring program that would be a powerful tool to inform decision-makers on coastal wetland conservation and restoration priorities throughout the Great Lakes basin

    Standardized Measures of Coastal Wetland Condition: Implementation at a Laurentian Great Lakes Basin-Wide Scale

    Get PDF
    Since European settlement, over 50 % of coastal wetlands have been lost in the Laurentian Great Lakes basin, causing growing concern and increased monitoring by government agencies. For over a decade, monitoring efforts have focused on the development of regional and organism-specific measures. To facilitate collaboration and information sharing between public, private, and government agencies throughout the Great Lakes basin, we developed standardized methods and indicators used for assessing wetland condition. Using an ecosystem approach and a stratified random site selection process, birds, anurans, fish, macroinvertebrates, vegetation, and physico-chemical conditions were sampled in coastal wetlands of all five Great Lakes including sites from the United States and Canada. Our primary objective was to implement a standardized basin-wide coastal wetland monitoring program that would be a powerful tool to inform decision-makers on coastal wetland conservation and restoration priorities throughout the Great Lakes basin

    Matter in Strong Magnetic Fields

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    The properties of matter are significantly modified by strong magnetic fields, B>>2.35×109B>>2.35\times 10^9 Gauss (1G=10−4Tesla1 G =10^{-4} Tesla), as are typically found on the surfaces of neutron stars. In such strong magnetic fields, the Coulomb force on an electron acts as a small perturbation compared to the magnetic force. The strong field condition can also be mimicked in laboratory semiconductors. Because of the strong magnetic confinement of electrons perpendicular to the field, atoms attain a much greater binding energy compared to the zero-field case, and various other bound states become possible, including molecular chains and three-dimensional condensed matter. This article reviews the electronic structure of atoms, molecules and bulk matter, as well as the thermodynamic properties of dense plasma, in strong magnetic fields, 109G<<B<1016G10^9G << B < 10^{16}G. The focus is on the basic physical pictures and approximate scaling relations, although various theoretical approaches and numerical results are also discussed. For the neutron star surface composed of light elements such as hydrogen or helium, the outermost layer constitutes a nondegenerate, partially ionized Coulomb plasma if B<<1014GB<<10^{14}G, and may be in the form of a condensed liquid if the magnetic field is stronger (and temperature <106<10^6 K). For the iron surface, the outermost layer of the neutron star can be in a gaseous or a condensed phase depending on the cohesive property of the iron condensate.Comment: 45 pages with 9 figures. Many small additions/changes. Accepted for publication in Rev. Mod. Phy
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