1,730 research outputs found
Environmental conditions of a salt-marsh biodiversity experiment on the island of Spiekeroog (Germany)
Field experiments investigating biodiversity and ecosystem functioning require the observation of abiotic parameters, especially when carried out in the intertidal zone. An experiment for biodiversityâecosystem functioning was set up in the intertidal zone of the back-barrier salt marsh of Spiekeroog Island in the German Bight. Here, we report the accompanying instrumentation, maintenance, data acquisition, data handling and data quality control as well as monitoring results observed over a continuous period from September 2014 to April 2017. Time series of abiotic conditions were measured at several sites in the vicinity of newly built experimental salt-marsh islands on the tidal flat. Meteorological measurements were conducted from a weather station (WS, https://doi.org/10.1594/PANGAEA.870988), oceanographic conditions were sampled through a bottom-mounted recording current meter (RCM, https://doi.org/10.1594/PANGAEA.877265) and a bottom-mounted tide and wave recorder (TWR, https://doi.org/10.1594/PANGAEA.877258). Tide data are essential in calculating flooding duration and flooding frequency with respect to different salt-marsh elevation zones. Data loggers (DL) for measuring the water level (DL-W, https://doi.org/10.1594/PANGAEA.877267), temperature (DL-T, https://doi.org/10.1594/PANGAEA.877257), light intensity (DL-L, https://doi.org/10.1594/PANGAEA.877256) and conductivity (DL-C, https://doi.org/10.1594/PANGAEA.877266) were deployed at different elevational zones on the experimental islands and the investigated salt-marsh plots. A data availability of 80% for 17 out of 23 sensors was achieved. Results showed the influence of seasonal and tidal dynamics on the experimental islands. Nearby salt-marsh plots exhibited some differences, e.g., in temperature dynamics. Thus, a consistent, multi-parameter, long-term dataset is available as a basis for further biodiversity and ecosystem functioning studies
Outlier robust corner-preserving methods for reconstructing noisy images
The ability to remove a large amount of noise and the ability to preserve
most structure are desirable properties of an image smoother. Unfortunately,
they usually seem to be at odds with each other; one can only improve one
property at the cost of the other. By combining M-smoothing and
least-squares-trimming, the TM-smoother is introduced as a means to unify
corner-preserving properties and outlier robustness. To identify edge- and
corner-preserving properties, a new theory based on differential geometry is
developed. Further, robustness concepts are transferred to image processing. In
two examples, the TM-smoother outperforms other corner-preserving smoothers. A
software package containing both the TM- and the M-smoother can be downloaded
from the Internet.Comment: Published at http://dx.doi.org/10.1214/009053606000001109 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Outcome of renal grafts after simultaneous kidney/ pancreas transplantation
Nineteen patients with endstage renal failure due to Type 1 (insulin-dependent) diabetes mellitus received simultaneous pancreas/kidney transplants using bladder drainage technique. Another group of 25 Type 1 diabetic patients received pancreas/kidney transplants by the duct occlusion technique. We observed a higher incidence of rejection episodes in the patients of the bladder drainage group than those in the duct occlusion group, 14 of 19 patients (74%) vs 7 of 25 (28%) respectively. Anti CD3 antibodies (Orthoclone, OKT3) as a part of induction treatment was used more often in the bladder drainage group (58%) than in the control group (20%)
Proteoglykane und die Verpackung von Exportproteinen: Interaction von Serglycin und ZG 16 in den Zymogengranula des exokrinen Rattenpankreas
In Vorarbeiten konnte das Proteoglykan Serglycin
in den Zymogengranula der Azinuszellen des exokrinen
Rattenpankreas als Bindungspartner des sekretorischen Lektins
ZG 16 identifiziert werden. Ferner konnte gezeigt werden, dass
das korrekt glykosylierte Serglycin fĂŒr die Sortierung von
Zymogenen in die Granula nötig ist (Biederbick et al., 2003).
Ziel dieser Arbeit war es, die Interaktion zwischen dem
ĂŒberwiegend membranstĂ€ndigen ZG 16 und Serglycin nĂ€her zu
analysieren, um Aufschluss ĂŒber Mechanismen der Verpackung und
Sortierung der Zymogene zu erhalten. DarĂŒber hinaus sollten
mögliche weitere Proteoglykane aus dem Inhalt der
Zymogengranula isoliert werden.
Es wurden folgende Ergebnisse
erzielt:
1. Durch Klonierung und Expression der
unverzuckerten, rekombinanten N- und C-terminalen Abschnitte
des Serglycin und deren Einsatz in Bindungsstudien
(Co-ImmunoprÀzipitation, GST-pull-down, Ligandenblots und
Crosslinkexperimenten) wurde festgestellt, dass die Interaktion
zwischen ZG 16 und Serglycin ĂŒber den unverzuckerten
N-terminalen Bereich (SGN) durch zuckerunabhÀngige
Protein-Protein-Wechselwirkungen erfolgt.
2. Die
Bindungssequenz des Serglycin an das ZG 16 konnte durch
Herstellung verschiedener Punkt- und Deletionsmutanten des
N-terminalen Bereichs SGN und deren Verwendung in
Bindungsstudien auf die 9 N-Terminus nahen AminosÀuren
ARYQWVRCK eingegrenzt werden.
3. Bei der Analyse der
hypothetischen SekundÀrstruktur des Serglycin, die mit Hilfe
des ExPASy Molecular Biology Server erstellt wurde, gab es sehr
starke Hinweise darauf, dass das Bindungsmotiv des Serglycin an
das ZG 16 ein b-Faltblatt darstellt.
Diese Daten zeigen, dass
Serglycin ĂŒber den N-terminalen unverzuckerten Abschnitt eine
Protein-Protein-Interaktion mit dem sekretorischen Lektin ZG 16
macht. Ăber diese Interaktion werden das Serglycin und ĂŒber
seine Glykosaminoglykan-Ketten assoziierte Zymogene an die
Zymogengranulamembran gebunden. Diese Wechselwirkung stellt
einen Sortierungsmechanismus fĂŒr die Zymogene in die Granula
dar.
4. FĂŒr das Vorhandensein weiterer Proteoglykane im
Inhalt der Zymogengranula (ZGI) konnten nur indirekte Hinweise
gefunden werden. Im Blyscan-Assay, einer FĂ€llung, die
spezifisch fĂŒr Proteoglykane ist, konnten durch
Extinktionsmessung Proteoglykane nachgewiesen werden. Die
gröĂte Extinktion wurde nach Vorbehandlung des ZGI mit NaHCO3
erhalten.
5. Die Zymogene scheinen mit Proteoglykanen
assoziiert zu sein. Durch diese Interaktion gelangt ein Teil
der Zymogene noch nach NaHCO3-Behandlung von ZGI und
anschlieĂender Blyscan- oder WesselfĂ€llung in das
Blyscanpellet, bzw. in die organische Phase der WesselfÀllung.
Durch EGTA-Inkubation von ZGI kann diese Interaktion zwischen
Proteoglykanen und Zymogenen aufgehoben werden. Hier erscheinen
keine Zymogene im Blyscanpellet oder der organischen Phase der
WesselfÀllung
Diversity and community biomass depend on dispersal and disturbance in microalgal communities
The evidence for species diversity effects
on ecosystem functions is mainly based on studies not
explicitly addressing local or regional processes
regulating coexistence or the importance of community
structure in terms of species evenness. In experimental
communities of marine benthic microalgae,
we altered the successional stages and thus the strength
of local species interactions by manipulating rates of
dispersal and disturbance. The treatments altered
realized species richness, evenness and community
biomass. For species richness, dispersal mattered only
at high disturbance rates; when opening new space,
dispersal led to maximized richness at intermediate
dispersal rates. Evenness, in contrast, decreased with
dispersal at low or no disturbance, i.e. at late successional stages. Community biomass showed a nonlinear
hump-shaped response to increasing dispersal at
all disturbance levels.We found a positive correlation
between richness and biomass at early succession, and
a strong negative correlation between evenness and
biomass at late succession. In early succession both
community biomass and richness depend directly on
dispersal from the regional pool, whereas the late
successional pattern shows that if interactions allow
the most productive species to become dominant,
diverting resources from this species (i.e. higher
evenness) reduces production. Our study emphasizes
the difference in biodiversityâfunction relationships
over time, as different mechanisms contribute to the
regulation of richness and evenness in early and late
successional stages
Eliminating Recursion from Monadic Datalog Programs on Trees
We study the problem of eliminating recursion from monadic datalog programs
on trees with an infinite set of labels. We show that the boundedness problem,
i.e., determining whether a datalog program is equivalent to some nonrecursive
one is undecidable but the decidability is regained if the descendant relation
is disallowed. Under similar restrictions we obtain decidability of the problem
of equivalence to a given nonrecursive program. We investigate the connection
between these two problems in more detail
On consistency of redescending M-kernel smoothers
Abstract M-estimators and M-kernel estimators with a redescending Ï-function are not in general consistent. This is often handled by means of coupling the estimator to a consistent one. Coupling the estimator to the (inconsistent) starting point improves the jump preserving properties. However, the consistency depends heavily on the shape of the density of the residuals. This paper shows inconsistency under convenient conditions as well as consistency-even at jump points-under somewhat stronger conditions
Hydration-Scanning Tunneling Microscopy as a Reliable Method for Imaging Biological Specimens and Hydrophilic Insulators
The recently discovered high lateral conductivity of molecularly thin adsorbed water films enables investigation of biological specimens, and even of surfaces of hydrophilic insulators by scanning tunneling microscopy (STM). Here we demonstrate the capabilities of this method, which we call hydration-STM (HSTM), with images of various specimens taken in humid atmosphere: We obtained images of a glass coverslip, collagen molecules, tobacco mosaic virus, lipid bilayers and cryosectioned bovine achilles tendon on mica. To elucidate the physical mechanism of this conduction phenomenon we recorded current-voltage curves on hydrated mica. This revealed a basically ohmic behavior of the J-V curves without a threshold voltage to activate the current transport and indicates that electrochemistry probably does not dominate the surface conductivity. We assume that the conduction mechanism is due to structuring of water at the surface
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