263 research outputs found
Research towards cross-media dialogue communication of municipalities using the example of the central Saxon university town of Mittweida
In der vorliegenden Arbeit findet eine Betrachtung der Möglichkeiten einer crossmedialen Dialogkommunikation in Kommunen am Beispiel der Hochschulstadt Mittweida statt. Es wird untersucht, wie Kommunen über eine vernetzte, interaktive, multisensorische sowie formal, inhaltlich und zeitlich integrierte Kommunikation ihre Bürger informieren und sie zu einem Dialog über lokal relevante Themen motivieren können. Dabei wird die Frage verfolgt, mit welchem Fokus Bürger im Rahmen einer solchen Kampagne kommunizieren und wie dabei der gewünschte Dialog entsteht. Datengrundlage für die Untersuchungen bilden Beobachtungen in den während der Kampagne Zukunftsstadt Mittweida etablierten und durch die Forschungsgruppe Crossmediale Medienwirkungsforschung an der Hochschule Mittweida weitergeführten Kanälen. Zudem wurde eine Befragung zum Stand der Kommunikation in sächsischen Kommunen durchgeführt. Die Ergebnisse zeigen, dass in einer crossmedialen Kommunikation in Kommunen Emotionen bei der Ansprache der Bürger eine bedeutende Rolle spielen und sich in den verschiedenen lokalen Medienkanälen Synergien entwickeln, die den Kommunikationserfolg mit den Bürgern stützen.This thesis contains an examination of the opportunities of cross-media dialogue communication in municipalities using the example of the university town of Mittweida. It is investigated how municipalities can inform their citizens through a cross-linked, interactive, multi-sensory as well as formal, content-linked and time integrated communication and motivate them for a dialogue about topics of local relevance. The central question pursued is with which focus citizens communicate in the context of a cross-media campaign and how the desired dialogue evolves. The data base of the investigations was formed by observation of the media-channels established during the campaign Zukunftsstadt Mittweida and later used by the cross-media media-impact research group at the University of Applied Sciences Mittweida. In addition, this thesis contains a survey about the state of communication in Saxon municipalities. The results show that emotion plays a major role in addressing the citizens in a cross-media communication in communities and that synergy evolves across different local media, supporting the success of
communication with the citizens
AtPTR4 and AtPTR6 are differentially expressed, tonoplast-localized members of the peptide transporter/nitrate transporter 1 (PTR/NRT1) family
Members of the peptide transporter/nitrate transporter 1 (PTR/NRT1) family in plants transport a variety of substrates like nitrate, di- and tripepetides, auxin and carboxylates. We isolated two members of this family from Arabidopsis, AtPTR4 and AtPTR6, which are highly homologous to the characterized di- and tripeptide transporters AtPTR1, AtPTR2 and AtPTR5. All known substrates of members of the PTR/NRT1 family were tested using heterologous expression in Saccharomyces cerevisiae mutants and oocytes of Xenopus laevis, but none could be identified as substrate of AtPTR4 or AtPTR6. AtPTR4 and AtPTR6 show distinct expression patterns, while AtPTR4 is expressed in the vasculature of the plants, AtPTR6 is highly expressed in pollen and during senescence. Phylogenetic analyses revealed that AtPTR2, 4 and 6 belong to one clade of subgoup II, whereas AtPTR1 and 5 are found in a second clade. Like AtPTR2, AtPTR4-GFP and AtPTR6-GFP fusion proteins are localized at the tonoplast. Vacuolar localization was corroborated by co-localization of AtPTR2-YFP with the tonoplast marker protein GFP-AtTIP2;1 and AtTIP1;1-GFP. This indicates that the two clades reflect different intracellular localization at the tonoplast (AtPTR2, 4, 6) and plasma membrane (AtPTR1, 5), respectivel
Systematic errors in weak lensing: application to SDSS galaxy-galaxy weak lensing
Weak lensing is emerging as a powerful observational tool to constrain
cosmological models, but is at present limited by an incomplete understanding
of many sources of systematic error. Many of these errors are multiplicative
and depend on the population of background galaxies. We show how the commonly
cited geometric test, which is rather insensitive to cosmology, can be used as
a ratio test of systematics in the lensing signal at the 1 per cent level. We
apply this test to the galaxy-galaxy lensing analysis of the Sloan Digital Sky
Survey (SDSS), which at present is the sample with the highest weak lensing
signal to noise and has the additional advantage of spectroscopic redshifts for
lenses. This allows one to perform meaningful geometric tests of systematics
for different subsamples of galaxies at different mean redshifts, such as
brighter galaxies, fainter galaxies and high-redshift luminous red galaxies,
both with and without photometric redshift estimates. We use overlapping
objects between SDSS and the DEEP2 and 2SLAQ spectroscopic surveys to establish
accurate calibration of photometric redshifts and to determine the redshift
distributions for SDSS. We use these redshift results to compute the projected
surface density contrast DeltaSigma around 259 609 spectroscopic galaxies in
the SDSS; by measuring DeltaSigma with different source samples we establish
consistency of the results at the 10 per cent level (1-sigma). We also use the
ratio test to constrain shear calibration biases and other systematics in the
SDSS survey data to determine the overall galaxy-galaxy weak lensing signal
calibration uncertainty. We find no evidence of any inconsistency among many
subsamples of the data.Comment: 39 pages, 19 figure
Galaxy Star Formation as a Function of Environment in the Early Data Release of the Sloan Digital Sky Survey
We present in this paper a detailed analysis of the effect of environment on the star formation activity of galaxies within the Early Data Release (EDR) of the Sloan Digital Sky Survey (SDSS). We have used the Halpha emission line to derive the star formation rate (SFR) for each galaxy within a volume-limited sample of 8598 galaxies with 0.05 less than or equal to z less than or equal to 0.095 and M (r*) less than or equal to 20.45. We find that the SFR of galaxies is strongly correlated with the local ( projected) galaxy density, and thus we present here a density-SFR relation that is analogous to the density-morphology relation. The effect of density on the SFR of galaxies is seen in three ways. First, the overall distribution of SFRs is shifted to lower values in dense environments compared with the field population. Second, the effect is most noticeable for the strongly star-forming galaxies (Halpha EW > 5 Angstrom) in the 75th percentile of the SFR distribution. Third, there is a break ( or characteristic density) in the density-SFR relation at a local galaxy density of similar to1 h(75)(-2) Mpc(-2). To understand this break further, we have studied the SFR of galaxies as a function of clustercentric radius from 17 clusters and groups objectively selected from the SDSS EDR data. The distribution of SFRs of cluster galaxies begins to change, compared with the field population, at a clustercentric radius of 3-4 virial radii (at the >1sigma statistical significance), which is consistent with the characteristic break in density that we observe in the density-SFR relation. This effect with clustercentric radius is again most noticeable for the most strongly star-forming galaxies. Our tests suggest that the density-morphology relation alone is unlikely to explain the density-SFR relation we observe. For example, we have used the ( inverse) concentration index of SDSS galaxies to classify late-type galaxies and show that the distribution of the star-forming (EW Halpha > 5Angstrom) late-type galaxies is different in dense regions ( within 2 virial radii) compared with similar galaxies in the field. However, at present, we are unable to make definitive statements about the independence of the density-morphology and density-SFR relation. We have tested our work against potential systematic uncertainties including stellar absorption, reddening, SDSS survey strategy, SDSS analysis pipelines, and aperture bias. Our observations are in qualitative agreement with recent simulations of hierarchical galaxy formation that predict a decrease in the SFR of galaxies within the virial radius. Our results are in agreement with recent 2dF Galaxy Redshift Survey results as well as consistent with previous observations of a decrease in the SFR of galaxies in the cores of distant clusters. Taken together, these works demonstrate that the decrease in SFR of galaxies in dense environments is a universal phenomenon over a wide range in density (from 0.08 to 10 h(75)(-2) Mpc(-2)) and redshift (out to z similar or equal to 0.5)
Sloan Digital Sky Survey III Photometric Quasar Clustering: Probing the Initial Conditions of the Universe using the Largest Volume
The Sloan Digital Sky Survey has surveyed 14,555 square degrees of the sky,
and delivered over a trillion pixels of imaging data. We present the
large-scale clustering of 1.6 million quasars between z = 0.5 and z = 2.5 that
have been classified from this imaging, representing the highest density of
quasars ever studied for clustering measurements. This data set spans ~11,000
square degrees and probes a volume of 80(Gpc/h)^3. In principle, such a large
volume and medium density of tracers should facilitate high-precision
cosmological constraints. We measure the angular clustering of photometrically
classified quasars using an optimal quadratic estimator in four redshift slices
with an accuracy of ~25% over a bin width of l ~10 - 15 on scales corresponding
to matter-radiation equality and larger (l ~ 2 - 30). Observational systematics
can strongly bias clustering measurements on large scales, which can mimic
cosmologically relevant signals such as deviations from Gaussianity in the
spectrum of primordial perturbations. We account for systematics by employing a
new method recently proposed by Agarwal et al. (2014) to the clustering of
photometrically classified quasars. We carefully apply our methodology to
mitigate known observational systematics and further remove angular bins that
are contaminated by unknown systematics. Combining quasar data with the
photometric luminous red galaxy (LRG) sample of Ross et al. (2011) and Ho et
al. (2012), and marginalizing over all bias and shot noise-like parameters, we
obtain a constraint on local primordial non-Gaussianity of fNL = -113+/-154
(1\sigma error). [Abridged]Comment: 35 pages, 15 figure
An infrared survey of brightest cluster galaxies: Paper I
We report on an imaging survey with the Spitzer Space Telescope of 62
brightest cluster galaxies with optical line emission. These galaxies are
located in the cores of X-ray luminous clusters selected from the ROSAT All-Sky
Survey. We find that about half of these sources have a sign of excess infrared
emission; 22 objects out of 62 are detected at 70 microns, 18 have 8 to 5.8
micron flux ratios above 1.0 and 28 have 24 to 8 micron flux ratios above 1.0.
Altogether 35 of 62 objects in our survey exhibit at least one of these signs
of infrared excess. Four galaxies with infrared excesses have a 4.5/3.6 micron
flux ratio indicating the presence of hot dust, and/or an unresolved nucleus at
8 microns. Three of these have high measured [OIII](5007A)/Hbeta flux ratios
suggesting that these four, Abell 1068, Abell 2146, and Zwicky 2089, and
R0821+07, host dusty active galactic nuclei (AGNs). 9 objects (including the
four hosting dusty AGNs) have infrared luminosities greater than 10^11 L_sol
and so can be classified as luminous infrared galaxies (LIRGs). Excluding the
four systems hosting dusty AGNs, the excess mid-infrared emission in the
remaining brightest cluster galaxies is likely related to star formation.Comment: accepted for publication in ApJ
General approach to reversing ketol-acid reductoisomerase cofactor dependence from NADPH to NADH
To date, efforts to switch the cofactor specificity of oxidoreductases
from nicotinamide adenine dinucleotide phosphate (NADPH) to nicotinamide
adenine dinucleotide (NADH) have been made on a case-by-
case basis with varying degrees of success. Here we present a
straightforward recipe for altering the cofactor specificity of a class of
NADPH-dependent oxidoreductases, the ketol-acid reductoisomerases
(KARIs). Combining previous results for an engineered NADH-dependent
variant of Escherichia coli KARI with available KARI crystal
structures and a comprehensive KARI-sequence alignment, we identified
key cofactor specificity determinants and used this information to
construct five KARIs with reversed cofactor preference. Additional directed
evolution generated two enzymes having NADH-dependent
catalytic efficiencies that are greater than the wild-type enzymes with
NADPH. High-resolution structures of a wild-type/variant pair reveal
the molecular basis of the cofactor switch
Hdelta-Selected Galaxies in the Sloan Digital Sky Survey I: The Catalog
[Abridged] We present here a new and homogeneous sample of 3340 galaxies
selected from the Sloan Digital Sky Survey (SDSS) based solely on the observed
strength of their Hdelta absorption line. These galaxies are commonly known as
``post-starburst'' or ``E+A'' galaxies, and the study of these galaxies has
been severely hampered by the lack of a large, statistical sample of such
galaxies. In this paper, we rectify this problem by selecting a sample of
galaxies which possess an absorption Hdelta equivalent width of EW(Hdelta_max)
- Delta EW(Hdelta_max) > 4A from 106682 galaxies in the SDSS. We have performed
extensive tests on our catalog including comparing different methodologies of
measuring the Hdelta absorption and studying the effects of stellar absorption,
dust extinction, emission-filling and measurement error. The measured abundance
of our Hdelta-selected (HDS) galaxies is 2.6 +/- 0.1% of all galaxies within a
volume-limited sample of 0.05<z<0.1 and M(r*)<-20.5, which is consistent with
previous studies of such galaxies in the literature. We find that only 25 of
our HDS galaxies in this volume-limited sample (3.5+/-0.7%) show no evidence
for OII and Halpha emission, thus indicating that true E+A (or k+a) galaxies
are extremely rare objects at low redshift, i.e., only 0.09+/-0.02% of all
galaxies in this volume-limited sample are true E+A galaxies. In contrast,
89+/-5% of our HDS galaxies in the volume-limited sample have significant
detections of the OII and Halpha emission lines. We find 27 galaxies in our
volume-limited HDS sample that possess no detectable OII emission, but do
however possess detectable Halpha emission. These galaxies may be dusty
star-forming galaxies. We provide the community with this new catalog of
Hdelta-selected galaxies to aid in the understanding of these galaxies.Comment: Submitted to PASJ. Catalog of galaxies available at
http://astrophysics.phys.cmu.edu/~tomo/ea
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