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Search Results: 1 - 10 of 413817 matches for " Andrea M. Siegel "
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The MHV68 M2 Protein Drives IL-10 Dependent B Cell Proliferation and Differentiation
Andrea M. Siegel,Jeremy H. Herskowitz,Samuel H. Speck
PLOS Pathogens , 2008, DOI: 10.1371/journal.ppat.1000039
Abstract: Murine gammaherpesvirus 68 (MHV68) establishes long-term latency in memory B cells similar to the human gammaherpesvirus Epstein Barr Virus (EBV). EBV encodes an interleukin-10 (IL-10) homolog and modulates cellular IL-10 expression; however, the role of IL-10 in the establishment and/or maintenance of chronic EBV infection remains unclear. Notably, MHV68 does not encode an IL-10 homolog, but virus infection has been shown to result in elevated serum IL-10 levels in wild-type mice, and IL-10 deficiency results in decreased establishment of virus latency. Here we show that a unique MHV68 latency-associated gene product, the M2 protein, is required for the elevated serum IL-10 levels observed at 2 weeks post-infection. Furthermore, M2 protein expression in primary murine B cells drives high level IL-10 expression along with increased secretion of IL-2, IL-6, and MIP-1α. M2 expression was also shown to significantly augment LPS driven survival and proliferation of primary murine B cells. The latter was dependent on IL-10 expression as demonstrated by the failure of IL10?/? B cells to proliferate in response to M2 protein expression and rescue of M2-associated proliferation by addition of recombinant murine IL-10. M2 protein expression in primary B cells also led to upregulated surface expression of the high affinity IL-2 receptor (CD25) and the activation marker GL7, along with down-regulated surface expression of B220, MHC II, and sIgD. The cells retained CD19 and sIgG expression, suggesting differentiation to a pre-plasma memory B cell phenotype. These observations are consistent with previous analyses of M2-null MHV68 mutants that have suggested a role for the M2 protein in expansion and differentiation of MHV68 latently infected B cells—perhaps facilitating the establishment of virus latency in memory B cells. Thus, while the M2 protein is unique to MHV68, analysis of M2 function has revealed an important role for IL-10 in MHV68 pathogenesis—identifying a strategy that appears to be conserved between at least EBV and MHV68.
Sociology of Objects Case Study: Terra-cotta Playing Hide-and-seek in the Art Worlds
Andrea Siegel
Music and Arts in Action , 2009,
Abstract: Sociological inquiry has been mostly absent from the investigation of mass-produced material goods, especially materials in the architectural arts. If sociology takes as a subject social networks in modern society — one of whose chief characteristics is mass production — then the “mutually determining” relationships between the material results of mass-production and social networks should have a central place in sociological study. Art worlds are constructed both by people and the objects they work with: people make objects which, in turn, influence people in an ongoing dialectic. By tracing aspects of architectural terra-cotta production through the modern period, this paper demonstrates that the specific investigation of a mass-produced art object, which is also a unique architectural and sculptural material, both lends itself to particular social networks in its use and creation and also brings greater richness to issues of sociological concern, including the importance of how the object itself plays a role in social networks, the exploration of architecture as art worlds, and the use of Becker’s “art worlds” concept to study mass production. In doing so, this article contributes new aspects of investigation to the study of art worlds, such as topics related to the roles of geography, technology, finances, mass media, labor competition, fashion, identity, durability and public safety, in combination with one another.
Attachment and Academic Classroom Behavior: Self-Efficacy and Procrastination as Moderators on the Influence of Attachment on Academic Success  [PDF]
Robert M. Kurland, Harold I. Siegel
Psychology (PSYCH) , 2016, DOI: 10.4236/psych.2016.78107
Abstract: Attachment, self-efficacy, and procrastination were measured in 161 college students enrolled in an Introductory Psychology class. Class grades and overall academic records were also obtained. Students who had higher levels of attachment anxiety had lower final grades in the class, higher levels of procrastination, and lower self-efficacy. Students with higher levels of attachment avoidance had lower grades within the class and a lower overall Grade Point Average (GPA). Regression analysis showed that self-efficacy moderated the relationship between attachment and class grade as well as overall GPA. Procrastination also moderated the relationship between both attachment anxiety and GPA and attachment avoidance and GPA.
Choices: The Science of Bela Julesz
Ralph M. Siegel
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0020172
Abstract:
Functional Implications of Sleep Development
Jerome M. Siegel
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0030178
Abstract:
Functional Implications of Sleep Development
Jerome M Siegel
PLOS Biology , 2005, DOI: 10.1371/journal.pbio.0030178
Abstract:
Choices: The Science of Bela Julesz
Ralph M Siegel
PLOS Biology , 2004, DOI: 10.1371/journal.pbio.0020172
Abstract:
Excitation of non-radial stellar oscillations by gravitational waves: a first model
D. M. Siegel,M. Roth
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.17240.x
Abstract: The excitation of solar and solar-like g modes in non-relativistic stars by arbitrary external gravitational wave fields is studied starting from the full field equations of general relativity. We develop a formalism that yields the mean-square amplitudes and surface velocities of global normal modes excited in such a way. The isotropic elastic sphere model of a star is adopted to demonstrate this formalism and for calculative simplicity. It is shown that gravitational waves solely couple to quadrupolar spheroidal eigenmodes and that normal modes are only sensitive to the spherical component of the gravitational waves having the same azimuthal order. The mean-square amplitudes in case of stationary external gravitational waves are given by a simple expression, a product of a factor depending on the resonant properties of the star and the power spectral density of the gravitational waves' spherical accelerations. Both mean-square amplitudes and surface velocities show a characteristic R^8-dependence (effective R^2-dependence) on the radius of the star. This finding increases the relevance of this excitation mechanism in case of stars larger than the Sun.
Excitation of stellar oscillations by gravitational waves: hydrodynamic model and numerical results for the Sun
D. M. Siegel,M. Roth
Physics , 2011, DOI: 10.1088/0004-637X/729/2/137
Abstract: Starting from a general relativistic framework a hydrodynamic formalism is derived that yields the mean-square amplitudes and rms surface velocities of normal modes of non-relativistic stars excited by arbitrary gravitational wave (GW) radiation. In particular, stationary GW fields are considered and the resulting formulae are evaluated for two general types of GW radiation: radiation from a particular astrophysical source (e.g., a binary system) and a stochastic background of gravitational waves (SBGW). Expected sources and signal strengths for both types of GW radiation are reviewed and discussed. Numerical results for the Sun show that low-order quadrupolar g modes are excited more strongly than p modes by orders of magnitude. Maximal rms surface velocities in the case of excitation by astrophysical sources are found to be v {\le} 10^(-8) mm/s, assuming GW strain amplitudes of h {\le} 10^(-20). It is shown that current models for an SBGW produced by cosmic strings, with Omega_GW ~ 10^(-8)-10^(-5) in the frequency range of solar g modes, are able to produce maximal solar g-mode rms surface velocities of 10^(-5)-10^(-3) mm/s. This result lies close to or within the amplitude range of 10^(-3)-1 mm/s expected from excitation by turbulent convection, which is currently considered to be responsible for stellar g-mode excitation. It is concluded that studying g-mode observations of stars other than the Sun, in which excitation by GWs could be even more effective due to different stellar structures, might provide a new method to either detect GWs or to deduce a significant direct upper limit on an SBGW at intermediate frequencies between the pulsar bound and the bounds from interferometric detectors on Earth.
A Functional Architecture of Optic Flow in the Inferior Parietal Lobule of the Behaving Monkey
Milena Raffi, Ralph M. Siegel
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000200
Abstract: The representation of navigational optic flow across the inferior parietal lobule was assessed using optical imaging of intrinsic signals in behaving monkeys. The exposed cortex, corresponding to the dorsal-most portion of areas 7a and dorsal prelunate (DP), was imaged in two hemispheres of two rhesus monkeys. The monkeys actively attended to changes in motion stimuli while fixating. Radial expansion and contraction, and rotation clockwise and counter-clockwise optic flow stimuli were presented concentric to the fixation point at two angles of gaze to assess the interrelationship between the eye position and optic flow signal. The cortical response depended upon the type of flow and was modulated by eye position. The optic flow selectivity was embedded in a patchy architecture within the gain field architecture. All four optic flow stimuli tested were represented in areas 7a and DP. The location of the patches varied across days. However the spatial periodicity of the patches remained constant across days at ~950 and 1100 μm for the two animals examined. These optical recordings agree with previous electrophysiological studies of area 7a, and provide new evidence for flow selectivity in DP and a fine scale description of its cortical topography. That the functional architectures for optic flow can change over time was unexpected. These and earlier results also from inferior parietal lobule support the inclusion of both static and dynamic functional architectures that define association cortical areas and ultimately support complex cognitive function.
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