William R. Hunt, Alaska: A Bicentennial History (New York: W. W. Norton &amp; Company, Inc., 1976, $8.95). Pp. xvi, 216. - David L. Lewis, District of Columbia: A Bicentennial History (New York: W. W. Norton &amp; Company, Inc., 1976, $8.95). Pp. xiv, 208.

Burchell, R. A.

doi:10.1017/s0021875800004874

Cited by 6 publications

(7 citation statements)

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“…A limited variety of bound orbits were found in addition to circular orbits. Generally these orbits are of the types discussed in advanced undergraduate classical mechanics texts [1][2][3][4]. These bound orbits include circular orbits and closed and open bound orbits that precess.…”

Section: Discussionmentioning

confidence: 99%

“…In the orbit calculations to follow, we will be considering only those orbits that are in the galactic plane and therefore we may use polar coordinates as shown in figure 4. In this coordinate system, the position vector, velocity and acceleration are respectively [1][2][3][4]…”

Section: Predictive Frameworkmentioning

confidence: 99%

“…One of the standard topics in an advanced undergraduate classical mechanics course is the study of orbits in situations where Newton's law of universal gravitation plays a central role [1][2][3][4]. Typically the discussion is focused on cases that are amenable to analytic solution such as the two-body problem where both bodies are spherical in shape and the orbits turn out to be the conic sections.…”

Section: Introductionmentioning

confidence: 99%

“…On occasion, non-spherical sources of gravitation are considered and this leads to bound orbits that precess. These bound orbits may be closed but are often open [1][2][3][4]. The precession of the earth's orbit due to an oblate sun is a case in point [2].…”

Section: Introductionmentioning

confidence: 99%

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Computation of bound orbits in the plane of a galaxy with a flat rotation curve

Bacon¹,

Sharrar²

2010

Eur. J. Phys.

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A standard topic in an advanced undergraduate classical mechanics course is the determination of the orbits in a gravitational field. In the present paper we report on the calculation of bound orbits in the gravitational field of a spiral galaxy. Calculations such as these could serve to focus attention on an area of cutting edge astrophysics and could serve as an instructive exercise for advanced undergraduates. In the computations given in this paper, use is made of real data on the flat rotation curve of NGC 3198 obtained by Begeman et al (van Albada et al 1985 Astrophys. J. 295 305–13; Begeman 1989 Astron. Astrophys. 223 47–60; Begeman 1987 PhD Thesis University of Groningen http://irs.ub.rug.nl/ppn/291578543), and a fitting of that data to a theoretical model outlined in a previous paper (Bacon and Sharrar 2010 Am. J. Phys. at press). The galaxy is modelled as a thin exponential disc of baryonic matter combined with a spherically symmetric dark matter halo. The bound orbits in the plane of the galaxy are investigated. The computations are carried out using an icon-driven systems-modelling program that avoids the need for extensive programming expertise. The range of orbits investigated includes bound circular orbits and bound closed and open orbits that precess. The bound closed and open orbits are bounded by circles generated by the loci of the apsides of the orbit.

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Section: Discussionmentioning

confidence: 99%

Section: Predictive Frameworkmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Computation of bound orbits in the plane of a galaxy with a flat rotation curve

Bacon¹,

Sharrar²

2010

Eur. J. Phys.

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“…So, therefore playing with the size of the plate we can get to control the length of the sound wave that produces a mirror reflection or diffraction of sound. We understand the diffraction of the sound wave breaking on plate, because of which the plate has similar length of the obstacle on which is breaking, as it is indicated by the Principle of Christian Huygens [4], [5].…”

Section: Concert Hall For Classical Music Wallsmentioning

confidence: 99%

A New M. Karlowicz Philharmonic Orchestra in Szczecin Poland

ARAU-PUCHADES

2023

Auditorium Acoustics 2015

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This paper describes a new concert Hall named: "M.Karlowicz Philharmonic, Szczecin". The acoustic design of the project was finished in 2009. It was built later and finally opened on 6 nd September 2014. The acoustics of the new Philharmonic hall have been very well received by audience public. In this report, we outline several acoustic aspects of design which were developed, obtaining a very result very excellent. Furthermore we show all acoustic results in detail.

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mRNA Vaccine-Induced SARS-CoV-2 Spike-Specific IFN-γ and IL-2 T-cell Responses are Predictive of Serological Neutralization and are Transiently Enhanced by Pre-Existing Cross-Reactive Immunity

Samaan,

Korosec,

Budylowski

et al. 2024

Preprint

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The contributions of SARS-CoV-2-specific T-cells to vaccine efficacy and durability are unclear. We investigated the relationships between mRNA vaccine-induced spike-specific IFN-gamma and IL-2 T-cell responses, anti-spike/RBD IgG/IgA antibodies, and live virus neutralizing capacity in long-term-care-home staff doubly vaccinated with BNT162b2 or mRNA-1273. The impacts of pre-existing cross-reactive T-cell immunity to SARS-CoV-2 on cellular and humoral responses to vaccination were additionally assessed. Mathematical modelling of the kinetics of spike-specific IFN-gamma and IL-2 T-cell responses over 6-months post-second dose was bifurcated into recipients who exhibited gradual increases (54% and 42%, respectively) with doubling times of 173 days, or decreases (46% and 58%, respectively) with half-lives of 115 days. Differences in kinetics did not correlate with any clinical phenotypes, although increases were proposed to be due to subclinical viral exposures. Serological anti-spike/RBD IgG/IgA antibody levels had otherwise decayed in all participants with half-lives of 55, 53, 76, and 59 days, respectively. Spike-specific T-cell responses induced at 2-6 weeks correlated with live viral neutralization at 6-months post-second dose, especially in hybrid immune individuals. Participants with pre-existing cross-reactive T-cell immunity to SARS-CoV-2 exhibited greater spike-specific T-cell responses, reduced anti-RBD IgA antibody levels, and a trending increase in neutralization at 2-6 weeks post-second dose. Non-spike-specific T-cells predominantly targeted SARS-CoV-2 non-structural protein at 6-months post-second dose in cross-reactive participants. mRNA vaccination was lastly shown to induce off-target T-cell responses against unrelated antigens. In summary, vaccine-induced spike-specific T-cell immunity appeared to influence serological neutralizing capacity, with only a modest effect induced by pre-existing cross-reactivity.

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William R. Hunt, Alaska: A Bicentennial History (New York: W. W. Norton & Company, Inc., 1976, $8.95). Pp. xvi, 216. - David L. Lewis, District of Columbia: A Bicentennial History (New York: W. W. Norton & Company, Inc., 1976, $8.95). Pp. xiv, 208.

Cited by 6 publications

References 0 publications

Computation of bound orbits in the plane of a galaxy with a flat rotation curve

Computation of bound orbits in the plane of a galaxy with a flat rotation curve

A New M. Karlowicz Philharmonic Orchestra in Szczecin Poland

mRNA Vaccine-Induced SARS-CoV-2 Spike-Specific IFN-γ and IL-2 T-cell Responses are Predictive of Serological Neutralization and are Transiently Enhanced by Pre-Existing Cross-Reactive Immunity

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