1,831 research outputs found

    The evolution of inverted magnetic fields through the inner heliosphere

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    Local inversions are often observed in the heliospheric magnetic field (HMF), but their origins and evolution are not yet fully understood.Parker Solar Probe has recently observed rapid, AlfvĂ©nic, HMF inversions in the inner heliosphere, known as ‘switchbacks’, which have been interpreted as the possible remnants of coronal jets. It has also been suggested that inverted HMF may be produced by near-Sun interchange reconnection; a key process in mechanisms proposed for slow solar wind release. These cases suggest that the source of inverted HMF is near the Sun, and it follows that these inversions would gradually decay and straighten as they propagate out through the heliosphere. Alternatively, HMF inversions could form during solar wind transit, through phenomena such velocity shears, draping over ejecta, or waves and turbulence. Such processes are expected to lead to a qualitatively radial evolution of inverted HMF structures. Using Helios measurements spanning 0.3–1 AU, we examine the occurrence rate of inverted HMF, as well as other magnetic field morphologies, as a function of radial distance r, and find that it continually increases. This trend may be explained by inverted HMF observed between 0.3–1 AU being primarily driven by one or more of the above in-transit processes, rather than created at the Sun. We make suggestions as to the relative importance of these different processes based on the evolution of the magnetic field properties associated with inverted HMF. We also explore alternative explanations outside of our suggested driving processes which may lead to the observed trend

    Parker Solar Probe observations of suprathermal electron flux enhancements originating from coronal hole boundaries

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    Reconnection between pairs of solar magnetic flux elements, one open and the other a closed loop, is theorised to be a crucial process for both maintaining the structure of the corona and producing the solar wind. This 'interchange reconnection' is expected to be particularly active at the open-closed boundaries of coronal holes (CHs). Previous analysis of solar wind data at 1AU indicated that peaks in the flux of suprathermal electrons at slow-fast stream interfaces may arise from magnetic connection to the CH boundary, rather than dynamic effects such as compression. Further, offsets between the peak and stream interface locations are suggested to be the result of interchange reconnection at the source. As a preliminary test of these suggestions, we analyse two solar wind streams observed during the first Parker Solar Probe (PSP) perihelion encounter, each associated with equatorial CH boundaries (one leading and one trailing with respect to rotation). Each stream features a peak in suprathermal electron flux, the locations and associated plasma properties of which are indicative of a solar origin, in agreement with previous suggestions from 1AU observations. Discrepancies between locations of the flux peaks and other features suggest these peaks may too be shifted by source region interchange reconnection. Our interpretation of each event is compatible with a global pattern of open flux transport, although random footpoint motions or other explanations remain feasible. These exploratory results highlight future opportunities for statistical studies regarding interchange reconnection and flux transport at CH boundaries with modern near-Sun missions

    Localization and Expression of Osteopontin in Mineralized and Nonmineralized Tissues of the Periodontium a

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72134/1/j.1749-6632.1995.tb44628.x.pd

    Isolation of murine cementoblasts: unique cells or uniquely‐positioned osteoblasts?

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109660/1/j.1600-0722.1998.tb02197.x.pd

    Use of MenACWY-CRM vaccine in children aged 2 through 23 months at increased risk for meningococcal disease: recommendations of the Advisory Committee on Immunization Practices, 2013

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    During its October 2013 meeting, the Advisory Committee on Immunization Practices (ACIP) recommended use of a third meningococcal conjugate vaccine, MenACWY-CRM (Menveo, Novartis), as an additional option for vaccinating infants aged 2 through 23 months at increased risk for meningococcal disease. MenACWY-CRM is the first quadrivalent meningococcal conjugate vaccine licensed for use in children aged 2 through 8 months. MenACWY-D (Menactra, Sanofi Pasteur) is recommended for use in children aged 9 through 23 months who are at increased risk for meningococcal disease, and Hib-MenCY-TT (MenHibrix, GlaxoSmithKline) is recommended for use in children aged 6 weeks through 18 months at increased risk. This report summarizes information on MenACWY-CRM administration in infants and provides recommendations for vaccine use in infants aged 2 through 23 months who are at increased risk for meningococcal disease. Because the burden of meningococcal disease in infants is low in the United States and the majority of cases that do occur are caused by serogroup B, which is not included in any vaccine licensed in the United States, only those infants who are at increased risk for meningococcal disease are recommended to receive a meningococcal vaccine

    Meningococcal vaccination: Recommendations of the advisory committee on immunization practices, United States, 2020

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    © 2020. This report compiles and summarizes all recommendations from CDC\u27s Advisory Committee on Immunization Practices (ACIP) for use of meningococcal vaccines in the United States. As a comprehensive summary and update of previously published recommendations, it replaces all previously published reports and policy notes. This report also contains new recommendations for administration of booster doses of serogroup B meningococcal (MenB) vaccine for persons at increased risk for serogroup B meningococcal disease. These guidelines will be updated as needed on the basis of availability of new data or licensure of new meningococcal vaccines. ACIP recommends routine vaccination with a quadrivalent meningococcal conjugate vaccine (MenACWY) for adolescents aged 11 or 12 years, with a booster dose at age 16 years. ACIP also recommends routine vaccination with MenACWY for persons aged ≄2 months at increased risk for meningococcal disease caused by serogroups A, C, W, or Y, including persons who have persistent complement component deficiencies; persons receiving a complement inhibitor (e.g., eculizumab [Soliris] or ravulizumab [Ultomiris]); persons who have anatomic or functional asplenia; persons with human immunodeficiency virus infection; microbiologists routinely exposed to isolates of Neisseria meningitidis; persons identified to be at increased risk because of a meningococcal disease outbreak caused by serogroups A, C, W, or Y; persons who travel to or live in areas in which meningococcal disease is hyperendemic or epidemic; unvaccinated or incompletely vaccinated first-year college students living in residence halls; and military recruits. ACIP recommends MenACWY booster doses for previously vaccinated persons who become or remain at increased risk. In addition, ACIP recommends routine use of MenB vaccine series among persons aged ≄10 years who are at increased risk for serogroup B meningococcal disease, including persons who have persistent complement component deficiencies; persons receiving a complement inhibitor persons who have anatomic or functional asplenia; microbiologists who are routinely exposed to isolates of N. meningitidis; and persons identified to be at increased risk because of a meningococcal disease outbreak caused by serogroup B. ACIP recommends MenB booster doses for previously vaccinated persons who become or remain at increased risk. In addition, ACIP recommends a MenB series for adolescents and young adults aged 16-23 years on the basis of shared clinical decision-making to provide short-term protection against disease caused by most strains of serogroup B N. meningitidis

    Ferrimagnetism in sputtered MnxCoGe thin films

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    Investigations into the magnetic properties of sputtered MnxCoGe films in the range 0.8 <= x <= 2.5 uncovered ferrimagnetic order, unlike the ferromagnetic order reported in bulk samples. These films formed hexagonal Ni2In-type structures in all measured compositions. While the Curie temperatures of the films are comparable to those of hexagonal bulk MnCoGe, here is a reduction in the magnetization of the MnxCoGe film relative to bulk MnCoGe, and a magnetization compensation point is observed in the x < 1 samples. To understand the behavior, we calculated the magnetic moments of Mn-antisite defects in MnCoGe with density-function theory calculations. Models constructed from the calculation suggest that films become ferrimagnetic due to the presence of Mn on the Co and Ge sites. In the x < 1 samples, these defects arose from the disorder in the films, whereas for x > 1, the excess Mn was driven onto the antisites and produced ferrimagnetic order.Comment: 8 pages, 7 figure
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