3,435 research outputs found
Magnetic Structure of Rapidly Rotating FK Comae-Type Coronae
We present a three-dimensional simulation of the corona of an FK Com-type
rapidly rotating G giant using a magnetohydrodynamic model that was originally
developed for the solar corona in order to capture the more realistic,
non-potential coronal structure. We drive the simulation with surface maps for
the radial magnetic field obtained from a stellar dynamo model of the FK Com
system. This enables us to obtain the coronal structure for different field
topologies representing different periods of time. We find that the corona of
such an FK Com-like star, including the large scale coronal loops, is dominated
by a strong toroidal component of the magnetic field. This is a result of part
of the field being dragged by the radial outflow, while the other part remains
attached to the rapidly rotating stellar surface. This tangling of the magnetic
field,in addition to a reduction in the radial flow component, leads to a
flattening of the gas density profile with distance in the inner part of the
corona. The three-dimensional simulation provides a global view of the coronal
structure. Some aspects of the results, such as the toroidal wrapping of the
magnetic field, should also be applicable to coronae on fast rotators in
general, which our study shows can be considerably different from the
well-studied and well-observed solar corona. Studying the global structure of
such coronae should also lead to a better understanding of their related
stellar processes, such as flares and coronal mass ejections, and in
particular, should lead to an improved understanding of mass and angular
momentum loss from such systems.Comment: Accepted to ApJ, 10 pages, 6 figure
Linking education and hospital data in England: linkage process and quality
Introduction: Linkage of administrative data for universal state education and National Health Service (NHS) hospital care would enable research into the inter-relationships between education and health for all children in England. /
Objectives: We aim to describe the linkage process and evaluate the uality of linkage of four one-year birth cohorts within the National Pupil Database (NPD) and Hospital Episode Statistics (HES). /
Methods: We used multi-step deterministic linkage algorithms to link longitudinal records from state schools to the chronology of records in the NHS Personal Demographics Service (PDS; linkage stage 1), and HES (linkage stage 2). We calculated linkage rates and compared pupil characteristics in linked and unlinked samples for each stage of linkage and each cohort (1990/91, 1996/97, 1999/00, and 2004/05). /
Results: Of the 2,287,671 pupil records, 2,174,601 (95%) linked to HES. Linkage rates improved over time (92% in 1990/91 to 99% in 2004/05). Ethnic minority pupils and those living in more deprived areas were less likely to be matched to hospital records, but differences in pupil characteristics between linked and unlinked samples were moderate to small.
Conclusion
We linked nearly all pupils to at least one hospital record. The high coverage of the linkage represents a unique opportunity for wide-scale analyses across the domains of health and education. However, missed links disproportionately affected ethnic minorities or those living in the poorest neighbourhoods: selection bias could be mitigated by increasing the quality and completeness of identifiers recorded in administrative data or the application of statistical methods that account for missed links
What Is an Act of Engagement? Between the Social, Collegial and Institutional Protocols
Engagement is not synonymous with commitment, even though both words are used in translations between English, French, and German. However, engagement is also not some supplementary phenomenon or a technical term that the phrase social acts already includes in itself or that the concepts of ‘commitment’ or ‘joint commitment’ somehow necessarily imply. In this article I would like to describe a special kind of social act and determine the function they have in relation between various agents. Most importantly, I would like to define their significance in the transformation of a group into an institution or higher order entity. My premise is that there are acts whose aim is to engage all others, since they refer to all of us together, and in so doing reduce negative (social) “acts” as well as various asocial behaviors within a group or institution. In this sense, engaged acts could alternatively also belong to a kind of institutional act, since they introduce certain adjustments to the institution, changing or modifying its rules, increasing its consistency and efficiency.First book series in Philosophy of the Social Sciences that specifically focuses on Philosophy of Sociality and Social Ontology.
Studies in the Philosophy of Sociality
Volume 1
The effect of combination treatment with aliskiren and blockers of the renin-angiotensin system on hyperkalaemia and acute kidney injury: systematic review and meta-analysis
Objective To examine the safety of using aliskiren combined with agents used to block the renin-angiotensin system
NESC Review of the 8-Foot High Temperature Tunnel (HTT) Oxygen Storage Pressure Vessel Inspection Requirements
The 8-Foot HTT (refer to Figure 4.0-1) is used to conduct tests of air-breathing hypersonic propulsion systems at Mach numbers 4, 5, and 7. Methane, Air, and LOX are mixed and burned in a combustor to produce test gas stream containing 21 percent by volume oxygen. The NESC was requested by the NASA LaRC Executive Safety Council to review the rationale for a proposed change to the recertification requirements, specifically the internal inspection requirements, of the 8-Foot HTT LOX Run Tank and LOX Storage Tank. The Run Tank is an 8,000 gallon cryogenic tank used to provide LOX to the tunnel during operations, and is pressured during the tunnel run to 2,250 pounds per square inch gage (psig). The Storage Tank is a 25,000 gallon cryogenic tank used to store LOX at slightly above atmospheric pressure as a external shell, with space between the shells maintained under vacuum conditions
Hole doping in compositionally complex correlated oxide enables tunable exchange biasing
Magnetic interfaces and the phenomena arising from them drive both the design
of modern spintronics and fundamental research. Recently, it was revealed that
through designing magnetic frustration in configurationally complex entropy
stabilized oxides, exchange bias can occur in structurally single crystal
films. This eliminates the need for complex heterostructures and nanocomposites
in the design and control of magnetic response phenomena. In this work, we
demonstrate through hole doping of a high entropy perovskite oxide that tuning
of magnetic responses can be achieved. With detailed magnetometry, we show
magnetic coupling exhibiting a variety of magnetic responses including exchange
bias and antiferromagnetic spin reversal in the entropy stabilized ABO3
perovskite oxide La1-xSrx(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 family. We find that
manipulation of the A-site charge state can be used to balance magnetic phase
compositions and coupling responses. This allows for the creation of highly
tunable exchange bias responses. In the low Sr doping regime, a spin frustrated
region arising at the antiferromagnetic phase boundary is shown to directly
couple to the antiferromagnetic moments of the film and emerges as the dominant
mechanism, leading to a vertical shift of magnetization loops in response to
field biasing. At higher concentrations, direct coupling of antiferromagnetic
and ferromagnetic regions is observed. This tunability of magnetic coupling is
discussed within the context of these three competing magnetic phases,
revealing critical features in designing exchange bias through exploiting spin
frustration and disorder in high entropy oxides
Qatar-2: A K dwarf orbited by a transiting hot Jupiter and a more massive companion in an outer orbit
We report the discovery and initial characterization of Qatar-2b, a hot
Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with a short
period, P_ b = 1.34 days. The mass and radius of Qatar-2b are M_p = 2.49 M_j
and R_p = 1.14 R_j, respectively. Radial-velocity monitoring of Qatar-2 over a
span of 153 days revealed the presence of a second companion in an outer orbit.
The Systemic Console yielded plausible orbits for the outer companion, with
periods on the order of a year and a companion mass of at least several M_j.
Thus Qatar-2 joins the short but growing list of systems with a transiting hot
Jupiter and an outer companion with a much longer period. This system
architecture is in sharp contrast to that found by Kepler for multi-transiting
systems, which are dominated by objects smaller than Neptune, usually with
tightly spaced orbits that must be nearly coplanar
Effects of caffeine on cognitive and autonomic measures in heavy and light caffeine consumers
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