134 research outputs found
The Sense of Church History in Representative Missouri Synod Theology
Based on representative Missouri Synod writings from the late 19th century, the author describes and documents an antihistorical bias that has provided impediments to an appropriate appreciation of church history in Missouri Synod theology
A Critique: “Two Levels of History.
It is scarcely possible to read a theological treatise today without at some point meeting the current distinction between two levels of history, between Historie, and Geschichte, (following the Bultmannians), or between outer and inner history ( H. Richard Niebuhr), or between the objective- historical and the existential-historical (John Macquarrie). This distinction has primarily been occasioned by the rise of the historical-critical method in the 19th century, by the failure of the so-called quest for the historical Jesus, and by the church\u27s apologetic needs in the scientific ( positivistic ) era. The primary aim of this paper is critically to examine this distinction, to point out certain difficulties that beset it, and to suggest a number of limitations that must be placed on the distinction if it is to retain its significance. In the process of criticism the paper will seek to reflect some of the concerns manifested in the contemporary philosophical analysis of religious discourse and, for that matter, in the overarching critique of the whole theological enterprise per se
Edge smoothing for real-time simulation of a polygon face object system as viewed by a moving observer
The visual system within an aircraft flight simulation system receives flight data and terrain data which is formated into a buffer memory. The image data is forwarded to an image processor which translates the image data into face vertex vectors Vf, defining the position relationship between the vertices of each terrain object and the aircraft. The image processor then rotates, clips, and projects the image data into two-dimensional display vectors (Vd). A display generator receives the Vd faces, and other image data to provide analog inputs to CRT devices which provide the window displays for the simulated aircraft. The video signal to the CRT devices passes through an edge smoothing device which prolongs the rise time (and fall time) of the video data inversely as the slope of the edge being smoothed. An operational amplifier within the edge smoothing device has a plurality of independently selectable feedback capacitors each having a different value. The values of the capacitors form a series which doubles as a power of two. Each feedback capacitor has a fast switch responsive to the corresponding bit of a digital binary control word for selecting (1) or not selecting (0) that capacitor. The control word is determined by the slope of each edge. The resulting actual feedback capacitance for each edge is the sum of all the selected capacitors and is directly proportional to the value of the binary control word. The output rise time (or fall time) is a function of the feedback capacitance, and is controlled by the slope through the binary control word
Galaxy growth by merging in the nearby universe
We measure the mass growth rate by merging for a wide range of galaxy types.
We present the small-scale (0.014 < r < 11 h70^{-1} Mpc) projected
cross-correlation functions w(rp) of galaxy subsamples from the spectroscopic
sample of the NYU VAGC (5 \times 10^5 galaxies of redshifts 0.03 < z < 0.15)
with galaxy subsamples from the SDSS imaging (4 \times 10^7 galaxies). We use
smooth fits to de-project the two-dimensional functions w(rp) to obtain smooth
three-dimensional real-space cross-correlation functions \xi(r) for each of
several spectroscopic subsamples with each of several imaging subsamples.
Because close pairs are expected to merge, the three-space functions and
dynamical evolution time estimates provide galaxy accretion rates. We find that
the accretion onto massive blue galaxies and onto red galaxies is dominated by
red companions, and that onto small-mass blue galaxies, red and blue galaxies
make comparable contributions. We integrate over all types of companions and
find that at fixed stellar mass, the total fractional accretion rates onto red
galaxies (\sim 1.5 h70 percent per Gyr) is greater than that onto blue galaxies
(\sim 0.5 h70 percent per Gyr). Although these rates are very low, they are
almost certainly over-estimates because we have assumed that all close pairs
merge as quickly as dynamical friction permits.Comment: submitted to APJ on 08/20/201
No More Active Galactic Nuclei in Clumpy Disks Than in Smooth Galaxies at z~2 in CANDELS / 3D-HST
We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to
investigate if active galactic nuclei (AGNs) are preferentially fueled by
violent disk instabilities funneling gas into galaxy centers at 1.3<z<2.4. We
select galaxies undergoing gravitational instabilities using the number of
clumps and degree of patchiness as proxies. The CANDELS visual classification
system is used to identify 44 clumpy disk galaxies, along with mass-matched
comparison samples of smooth and intermediate morphology galaxies. We note
that, despite being being mass-matched and having similar star formation rates,
the smoother galaxies tend to be smaller disks with more prominent bulges
compared to the clumpy galaxies. The lack of smooth extended disks is probably
a general feature of the z~2 galaxy population, and means we cannot directly
compare with the clumpy and smooth extended disks observed at lower redshift.
We find that z~2 clumpy galaxies have slightly enhanced AGN fractions selected
by integrated line ratios (in the mass-excitation method), but the spatially
resolved line ratios indicate this is likely due to extended phenomena rather
than nuclear AGNs. Meanwhile the X-ray data show that clumpy, smooth, and
intermediate galaxies have nearly indistinguishable AGN fractions derived from
both individual detections and stacked non-detections. The data demonstrate
that AGN fueling modes at z~1.85 - whether violent disk instabilities or
secular processes - are as efficient in smooth galaxies as they are in clumpy
galaxies.Comment: ApJ accepted. 17 pages, 17 figure
Galaxy Pairs in the Sloan Digital Sky Survey - II: The Effect of Environment on Interactions
We use a sample of close galaxy pairs selected from the Sloan Digital Sky
Survey Data Release 4 (SDSS DR4) to investigate in what environments galaxy
mergers occur and how the results of these mergers depend on differences in
local galaxy density. The galaxies are quantified morphologically using
two-dimensional bulge-plus-disk decompositions and compared to a control sample
matched in stellar mass, redshift and local projected density. Lower density
environments have fractionally more galaxy pairs with small projected
separations (r_p) and relative velocities (Delta v), but even high density
environments contain significant populations of pairs with parameters that
should be conducive to interactions. Metrics of asymmetry and colour are used
to identify merger activity and triggered star formation. The location of star
formation is inferred by distinguishing bulge and disk colours and calculating
bulge fractions from the SDSS images. Galaxies in the lowest density
environments show the largest changes in star formation rate, asymmetry and
bulge-total fractions at small separations, accompanied by bluer bulge colours.
At the highest local densities, the only galaxy property to show an enhancement
in the closest pairs is asymmetry. We interpret these results as evidence that
whilst interactions (leading to tidal distortions) occur at all densities,
triggered star formation is seen only in low-to-intermediate density
environments. We suggest that this is likely due to the typically higher gas
fractions of galaxies in low density environments. Finally, by
cross-correlating our sample of galaxy pairs with a cluster catalogue, we
investigate the dependence of interactions on clustercentric distance. It is
found that for close pairs the fraction of asymmetric galaxies is highest in
the cluster centres.Comment: Accepted by MNRAS, 15 page
Oncofertility: combination of ovarian stimulation with subsequent ovarian tissue extraction on the day of oocyte retrieval
Background New anticancer treatments have increased survival rates for cancer patients, but often at the cost of sterility. Several strategies are currently available for preserving fertility. However, the chances of achieving a pregnancy with one technique are still limited. A combination of methods is therefore recommended in order to maximize women’s chances of future fertility. In this retrospective study, ovarian stimulation with subsequent ovarian tissue extraction on the day of oocyte retrieval were combined and the quality of the ovarian tissue, the numbers and quality of oocytes, time requirements, and the safety of the strategy were examined. Methods Fourteen female patients suffering from malignant diseases underwent one in vitro fertilization cycle. Different stimulation protocols were used, depending on the menstrual cycle. Transvaginal oocyte retrieval was scheduled 34–36 h after human chorionic gonadotropin administration. Immediately afterwards, ovarian tissue was extracted laparoscopically. Results A mean of 10 oocytes were retrieved per patient, and 67% of the oocytes were successfully fertilized using intracytoplasmic sperm injection. No periprocedural complications and no complications leading to postponement of the start of chemotherapy occurred. The ovarian tissues were of good quality, with a normal age-related follicular distribution and without carcinoma cell invasion. Conclusions An approach using ovarian stimulation first, followed by laparoscopic collection of ovarian tissue, is a useful strategy for increasing the efficacy of fertility preservation techniques. The ovarian tissue is not affected by prior ovarian stimulation
The HST/ACS Coma Cluster Survey. II. Data Description and Source Catalogs
The Coma cluster was the target of a HST-ACS Treasury program designed for
deep imaging in the F475W and F814W passbands. Although our survey was
interrupted by the ACS instrument failure in 2007, the partially completed
survey still covers ~50% of the core high-density region in Coma. Observations
were performed for 25 fields that extend over a wide range of cluster-centric
radii (~1.75 Mpc) with a total coverage area of 274 arcmin^2. The majority of
the fields are located near the core region of Coma (19/25 pointings) with six
additional fields in the south-west region of the cluster. In this paper we
present reprocessed images and SExtractor source catalogs for our survey
fields, including a detailed description of the methodology used for object
detection and photometry, the subtraction of bright galaxies to measure faint
underlying objects, and the use of simulations to assess the photometric
accuracy and completeness of our catalogs. We also use simulations to perform
aperture corrections for the SExtractor Kron magnitudes based only on the
measured source flux and half-light radius. We have performed photometry for
~73,000 unique objects; one-half of our detections are brighter than the
10-sigma point-source detection limit at F814W=25.8 mag (AB). The slight
majority of objects (60%) are unresolved or only marginally resolved by ACS. We
estimate that Coma members are 5-10% of all source detections, which consist of
a large population of unresolved objects (primarily GCs but also UCDs) and a
wide variety of extended galaxies from a cD galaxy to dwarf LSB galaxies. The
red sequence of Coma member galaxies has a constant slope and dispersion across
9 magnitudes (-21<M_F814W<-13). The initial data release for the HST-ACS Coma
Treasury program was made available to the public in 2008 August. The images
and catalogs described in this study relate to our second data release.Comment: Accepted for publication in ApJS. A high-resolution version is
available at http://archdev.stsci.edu/pub/hlsp/coma/release2/PaperII.pd
Galaxy Pairs in the Sloan Digital Sky Survey - III: Evidence of Induced Star Formation from Optical Colours
We have assembled a large, high quality catalogue of galaxy colours from the
Sloan Digital Sky Survey Data Release 7, and have identified 21,347 galaxies in
pairs spanning a range of projected separations (r_p < 80 h_{70}^{-1} kpc),
relative velocities (\Delta v < 10,000 km/s, which includes projected pairs
that are essential for quality control), and stellar mass ratios (from 1:10 to
10:1). We find that the red fraction of galaxies in pairs is higher than that
of a control sample matched in stellar mass and redshift, and demonstrate that
this difference is likely due to the fact that galaxy pairs reside in higher
density environments than non-paired galaxies. We detect clear signs of
interaction-induced star formation within the blue galaxies in pairs, as
evidenced by a higher fraction of extremely blue galaxies, along with blueward
offsets between the colours of paired versus control galaxies. These signs are
strongest in close pairs (r_p < 30 h_{70}^{-1} kpc and \Delta v < 200 km/s),
diminish for more widely separated pairs (r_p > 60 h_{70}^{-1} kpc and \Delta v
< 200 km/s) and disappear for close projected pairs (r_p < 30 h_{70}^{-1} kpc
and \Delta v > 3000 km/s). These effects are also stronger in central (fibre)
colours than in global colours, and are found primarily in low- to
medium-density environments. Conversely, no such trends are seen in red
galaxies, apart from a small reddening at small separations which may result
from residual errors with photometry in crowded fields. When interpreted in
conjunction with a simple model of induced starbursts, these results are
consistent with a scenario in which close peri-centre passages trigger induced
star formation in the centres of galaxies which are sufficiently gas rich,
after which time the galaxies gradually redden as they separate and their
starbursts age.Comment: 17 pages. Accepted for publication in MNRA
No More Active Galactic Nuclei in Clumpy Disks than in Smooth Galaxies at \u3cem\u3ez\u3c/em\u3e ~ 2 in CANDELS/3D-HST*
We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3 \u3c z \u3c 2.4. We select galaxies undergoing gravitational instabilities using the number of clumps and degree of patchiness as proxies. The CANDELS visual classification system is used to identify 44 clumpy disk galaxies, along with mass-matched comparison samples of smooth and intermediate morphology galaxies. We note that despite being mass-matched and having similar star formation rates, the smoother galaxies tend to be smaller disks with more prominent bulges compared to the clumpy galaxies. The lack of smooth extended disks is probably a general feature of the z ~ 2 galaxy population, and means we cannot directly compare with the clumpy and smooth extended disks observed at lower redshift. We find that z ~ 2 clumpy galaxies have slightly enhanced AGN fractions selected by integrated line ratios (in the mass-excitation method), but the spatially resolved line ratios indicate this is likely due to extended phenomena rather than nuclear AGNs. Meanwhile, the X-ray data show that clumpy, smooth, and intermediate galaxies have nearly indistinguishable AGN fractions derived from both individual detections and stacked non-detections. The data demonstrate that AGN fueling modes at z ~ 1.85—whether violent disk instabilities or secular processes—are as efficient in smooth galaxies as they are in clumpy galaxies
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