4,118 research outputs found
Preaching in the World of Electronic Technology-Implicatiions for Homiletics in the Message of H. Marshall Mcluhan
The contemporary communications environment is described in this thesis for the purpose of determining the ways in which it conditions the learning and perception of modern man. The basic resource is the writing of Herbert Marshall McLuhan, Director of the Center for Culture and Technology at the University of Toronto and author of several books about the media. His understanding of the history of media and his descriptions of the electronic environment and modern man constitute a comprehensive analysis of communications in the current era. McLuhan\u27s background, his expressed assumptions, and basic resources are described in order to provide a better understanding of his writings. Major themes from his works about the media are examined in order to isolate those which have implications for Christian preaching. An overview of positive and negative criticisms of McLuhan\u27s work exposes some of his strengths and weaknesses. Finally, Christian preaching is examined through a historical survey, giving special attention to the homiletic task in the electronic environment. The study concludes with a discussion of ways in which the media assist or detract from the communication of the Gospel. Some practical observations about what the media can and cannot do to aid the task of preaching are made. These place McLuhan\u27s ideas into perspective and draw from him those insights which can assist Christian preachers
Phonon spectral function for an interacting electron-phonon system
Using exact diagonalzation techniques, we study a model of interacting
electrons and phonons. The spectral width of the phonons is found to be reduced
as the Coulomb interaction U is increased. For a system with two modes per
site, we find a transfer of coupling strength from the upper to the lower mode.
This transfer is reduced as U is increased. These results give a qualitative
explanation of differences between Raman and photoemission estimates of the
electron-phonon coupling constants for A3C60 (A= K, Rb).Comment: 4 pages, RevTeX, 2 eps figur
Analysis of the circumstellar environment of the B[e] star HD 45677 (FS CMa)
We studied the circumstellar environment of the B[e] star HD 45677 through
the analysis of the emission lines from ionized metals. We used the statistical
approach of the self absorption curve method (SAC) to derive physical
parameters of the line emitting region. The Fe II and Cr II double-peaked
emission line structure is explained by the presence of a thin absorption
component red shifted by ~3 km/s. This absorption component can be interpreted
geometricaly as being due to infalling material perpendicularly to the disk
seen nearly pole-on, as indicated by the emission line structure. The Cr II and
Fe II emission lines have a complex structure with two (narrow and broad)
components, of 45 and 180 km/s FWHM for the permitted lines and 25 and 100 km/s
FWHM for the forbidden ones, respectively. We argue that the narrow components
are principaly emitted by an optically thin disk seen nearly pole-on, in a
region whose minimum radius is estimated to be 4 10^12 cm, while the broad ones
are formed in a disk-linked wind.Comment: 14 pages, submitted to Astronomy and Astrophysic
Hayabusa Re-Entry: Trajectory Analysis and Observation Mission Design
On June 13th, 2010, the Hayabusa sample return capsule successfully re-entered Earth s atmosphere over the Woomera Prohibited Area in southern Australia in its quest to return fragments from the asteroid 1998 SF36 Itokawa . The sample return capsule entered at a super-orbital velocity of 12.04 km/sec (inertial), making it the second fastest human-made object to traverse the atmosphere. The NASA DC-8 airborne observatory was utilized as an instrument platform to record the luminous portion of the sample return capsule re-entry (~60 sec) with a variety of on-board spectroscopic imaging instruments. The predicted sample return capsule s entry state information at ~200 km altitude was propagated through the atmosphere to generate aerothermodynamic and trajectory data used for initial observation flight path design and planning. The DC- 8 flight path was designed by considering safety, optimal sample return capsule viewing geometry and aircraft capabilities in concert with key aerothermodynamic events along the predicted trajectory. Subsequent entry state vector updates provided by the Deep Space Network team at NASA s Jet Propulsion Laboratory were analyzed after the planned trajectory correction maneuvers to further refine the DC-8 observation flight path. Primary and alternate observation flight paths were generated during the mission planning phase which required coordination with Australian authorities for pre-mission approval. The final observation flight path was chosen based upon trade-offs between optimal viewing requirements, ground based observer locations (to facilitate post-flight trajectory reconstruction), predicted weather in the Woomera Prohibited Area and constraints imposed by flight path filing deadlines. To facilitate sample return capsule tracking by the instrument operators, a series of two racetrack flight path patterns were performed prior to the observation leg so the instruments could be pointed towards the region in the star background where the sample return capsule was expected to become visible. An overview of the design methodologies and trade-offs used in the Hayabusa re-entry observation campaign are presented
Liberating Critical Theory: Eurocentrism, Normativity, and Capitalism: Symposium on Amy Allen’s The End of Progress: Decolonizing the Normative Foundations of Critical Theory, Columbia University Press, 2016
Kinematical structure of the circumstellar environments of galactic B[e]-type stars
High resolution line profiles are presented for selected forbidden and
permitted emission lines of a sample of galactic B[e]-type stars. The spectral
resolution corresponds to 5-7 km/s with the exception of some line profiles
which were observed with a resolution of 9-13 km/s. All Ha profiles are
characterized by a narrow split or single emission component with a width of
about 150-250 km/s (FWHM) and broad wings with a full width of ~1000-2000 km/s.
The Ha profiles can be classified into three groups: double-peaked profiles
representing the majority, single-peaked emission-line profiles, and normal P
Cygni-type profiles. The forbidden lines exhibit in most cases double-peaked
profiles. The split forbidden line profiles have peak separations of as little
as 10 km/s. The ratio of violet to red emission peak intensities, V/R, is
predominantly smaller or equal to 1. Theoretical profiles were calculated for
the optically thin case. A latitude-dependent stellar wind with a radial
expansion and a velocity decreasing from the pole to the equator was adopted.
In addition an equatorial dust ring with various optical depths was assumed.
This model can explain split lines and line asymmetries observed in some stars.
Moreover, the V/R ratios can be understood in terms of this model. The
comparison of the observed line profiles with the models thus confirms the
assumption of disk-like line-formation regions as commonly adopted for
B[e]-type stars.Comment: Astronomy & Astrophysics, in pres
Early-type objects in NGC6611 and Eagle Nebula
An important question about Be stars is whether Be stars are born as Be stars
or not. It is necessary to observe young clusters to answer this question.
Observations of stars in NGC6611 and the star-formation region of Eagle Nebula
have been carried out with the ESO-WFI in slitless spectroscopic mode and at
the VLT-GIRAFFE. The targets for the GIRAFFE observations were pre-selected
from the literature and our catalogue of emission-line stars (ELS) based on the
WFI study. GIRAFFE observations allowed us to study accurately the population
of the early-type stars with and without emission lines. For this study, we
determined the fundamental parameters of OBA stars. We also studied the status
of the objects (main sequence or pre-main sequence stars) by using IR data,
membership probabilities, and location in HR diagrams. The nature of the
early-type ELS in M16 is derived. The slitless observations with the WFI
clearly indicate a small number of ELS in M16. We observed with GIRAFFE 101 OBA
stars, among them 9 are ELS with circumstellar emission in Halpha. We found
that: W080 could be a new He-strong star, like W601. W301 is a possible
classical Be star, W503 is a mass-transfer eclipsing binary with an accretion
disk, and the other ones are possible Herbig Ae/Be stars. We also found that
the rotational velocities of main sequence B stars are 18% lower than those of
pre-main sequence B stars, in good agreement with theory about the evolution of
rotational velocities. Combining different indications and technics, we found
that 27% of the B-type stars are binaries. We also redetermined the age of
NGC6611 found equal to 1.2--1.8 Myears in good agreement with the most recent
determinations.Comment: Accepted by A&A, english not yet correcte
2-{(E)-N-[2-(1H-Inden-3-yl)ethyl]iminomethyl}-1H-imidazole
The asymmetric unit of the title compound, C15H15N3, contains two crystallographically independent molecules with very similar geometries. The imidazole and indenyl planes are approximately orthogonal, making dihedral angles of 88.21 (9) and 83.08 (9)%deg; in the two independent molecules. In the crystal, the imidazole units are linked by N—H⋯N hydrogen bonds into chains parallel to the 101) plane stretched in the diagonal direction [translation vector (,1,0); C(4) motif]. Within a chain, there are two types of symmetrically non-equivalent alternating H-bonds which slightly differ in their parameters
The Enigmatic Young Object: Walker 90/V590 Monocerotis
We assess the evolutionary status of the intriguing object Walker 90/V590
Mon, which is located about 20 arcminutes northwest of the Cone Nebula near the
center of the open cluster NGC 2264. This object, according to its most recent
optical spectral type determination (B7), which we confirmed, is at least 3
magnitudes too faint in V for the cluster distance, but it shows the classical
signs of a young pre-main sequence object, such as highly variable Halpha
emission, Mg II emission, IR excess, UV continuum, and optical variability. We
analyzed a collection of archival and original data on Walker 90, covering 45
years including photometry, imaging, and spectroscopic data ranging from
ultraviolet to near-infrared wavelengths. According to star formation
processes, it is expected that, as this object clears its primordial
surroundings, it should become optically brighter, show a weakening of its IR
excess and present decreasing line emissions. This behavior is supported by our
observations and analysis, but timescales are expected to be longer than the
one observed here. Based on photometric data secured in 2007, we find Walker 90
at its brightest recorded optical magnitude. We document an evolution in
spectral type over the past five decades (from A2/A3 to currently B7 and as
early as B4), along with a decrease in the near-infrared K fluxes. From
near-infrared images secured in 2004, Walker 90 appears as a point source
placing an upper limit of 0.1 arcsec for its diameter. We conclude that many
observational features are explained if W90 is a flared disk system, surrounded
by an inclined optically thick accretion disk.Comment: 13 pages, 19 figure
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