1,122 research outputs found
Long-term data reveal contrasting impacts of native versus invasive nest predators in Iceland
Bird species on islands are strongly impacted by biological invasions, with the Icelandic common eider (Somateria mollissima borealis) being particularly threatened. Down collection by local families in BreiĂ°afjĂśrĂ°ur, West Iceland, provided long-term datasets of nests from two archipelagos, covering 95 islands over 123âyears and 39 islands over 27âyears, respectively. Using these exceptional datasets, we found that the arrival of the invasive semi-aquatic American mink (Neogale vison) was a more impactful driver of population dynamics than climate. This invasive predator heavily reduced eider nest numbers by ca. 60% in the Brokey archipelago. In contrast, we detected an apparently adaptive response to the return of the native fox in the Purkey archipelago, with dense nests on islands inaccessible to the fox and no apparent impact on eider populations. This difference might be due to the eiders lacking a joint evolutionary history with the mink and therefore lacking appropriate antipredator responses
Prozessstrategien zur optimalen Reinigungsfähigkeit am Beispiel des Titus-Zentrifugentrockners TZT 400
Improving parsing of spontaneous speech with the help of prosodic boundaries
Parsing can be improved in automatic speech understanding if prosodic boundary marking is taken into account, because syntactic boundaries are often marked by prosodic means. Because large databases are needed for the training of statistical models for prosodic boundaries, we developed a labeling scheme for syntactic-prosodic boundaries within the German VERBMOBIL project (automatic speech-to-speech translation). We compare the results of classifiers (multi-layer perceptrons and language models) trained on these syntactic-prosodic boundary labels with classifiers trained on perceptual-prosodic and purely syntactic labels. Recognition rates of up to 96% were achieved. The turns that we need to parse consist of 20 words on the average and frequently contain sequences of partial sentence equivalents due to restarts, ellipsis, etc. For this material, the boundary scores computed by our classifiers can successfully be integrated into the syntactic parsing of word graphs; currently, they improve the parse time by 92% and reduce the number of parse trees by 96%. This is achieved by introducing a special Prosodic Syntactic Clause Boundary symbol (PSCB) into our grammar and guiding the search for the best word chain with the prosodic boundary scores
Molecular serum signature of treatment resistant depression
Rationale:
A substantial number of patients suffering from major depressive disorder (MDD) do not respond to multiple trials of anti-depressants, develop a chronic course of disease and become treatment resistant. Most of the studies investigating molecular changes in treatment-resistant depression (TRD) have only examined a limited number of molecules and genes. Consequently, biomarkers associated with TRD are still lacking.
Objectives:
This study aimed to use recently advanced high-throughput proteomic platforms to identify peripheral biomarkers of TRD defined by two staging models, the Thase and Rush staging model (TRM) and the Maudsley Staging Model (MSM).
Methods:
Serum collected from an inpatient cohort of 65 individuals suffering from MDD was analysed using two different mass spectrometric-based platforms, label-free liquid chromatography mass spectrometry (LC-MSE) and selective reaction monitoring (SRM), as well as a multiplex bead based assay.
Results:
In the LC-MSE analysis, proteins involved in the acute phase response and complement activation and coagulation were significantly different between the staging groups in both models. In the multiplex bead-based assay analysis TNF-Îą levels (log(odds)â=ââ4.95, pâ=â0.045) were significantly different in the TRM comparison.
Using SRM, significant changes of three apolipoproteins AâI (βâ=â0.029, pâ=â0.035), M (βâ=ââ0.017, pâ=â0.009) and F (βâ=ââ0.031, pâ=â0.024) were associated with the TRM but not the MSM.
Conclusion:
Overall, our findings suggest that proteins, which are involved in immune and complement activation, may represent potential biomarkers that could be used by clinicians to identify high-risk patients. Nevertheless, given that the molecular changes between the staging groups were subtle, the results need to be interpreted cautiously
Mapping Tumor Spheroid Mechanics in Dependence of 3D Microenvironment Stiffness and Degradability by Brillouin Microscopy
Altered biophysical properties of cancer cells and of their microenvironment contribute to cancer progression. While the relationship between microenvironmental stiffness and cancer cell mechanical properties and responses has been previously studied using two-dimensional (2D) systems, much less is known about it in a physiologically more relevant 3D context and in particular for multicellular systems. To investigate the influence of microenvironment stiffness on tumor spheroid mechanics, we first generated MCF-7 tumor spheroids within matrix metalloproteinase (MMP)-degradable 3D polyethylene glycol (PEG)-heparin hydrogels, where spheroids showed reduced growth in stiffer hydrogels. We then quantitatively mapped the mechanical properties of tumor spheroids in situ using Brillouin microscopy. Maps acquired for tumor spheroids grown within stiff hydrogels showed elevated Brillouin frequency shifts (hence increased longitudinal elastic moduli) with increasing hydrogel stiffness. Maps furthermore revealed spatial variations of the mechanical properties across the spheroidsâ cross-sections. When hydrogel degradability was blocked, comparable Brillouin frequency shifts of the MCF-7 spheroids were found in both compliant and stiff hydrogels, along with similar levels of growth-induced compressive stress. Under low compressive stress, single cells or free multicellular aggregates showed consistently lower Brillouin frequency shifts compared to spheroids growing within hydrogels. Thus, the spheroidsâ mechanical properties were modulated by matrix stiffness and degradability as well as multicellularity, and also to the associated level of compressive stress felt by tumor spheroids. Spheroids generated from a panel of invasive breast, prostate and pancreatic cancer cell lines within degradable stiff hydrogels, showed higher Brillouin frequency shifts and less cell invasion compared to those in compliant hydrogels. Taken together, our findings contribute to a better understanding of the interplay between cancer cells and microenvironment mechanics and degradability, which is relevant to better understand cancer progression
Polyhedral units and network connectivity in calcium aluminosilicate glasses from high-energy x-ray diffraction
Structure factors for Cax/2AlxSi1-xO2 glasses (x=0,0.25,0.5,0.67) extended to
a wave vector of magnitude Q= 40 1/A have been obtained by high-energy x-ray
diffraction. For the first time, it is possible to resolve the contributions of
Si-O, Al-O and Ca-O coordination polyhedra to the experimental atomic pair
distribution functions (PDF). It has been found that both Si and Al are
four-fold coordinated and so participate in a continuous tetrahedral network at
low values of x. The number of network breaking defects in the form of
non-bridging oxygens (NBO's) increases slowly with x until x=0.5 (NBO's ~ 10%
at x=0.5). By x=0.67 the network breaking defects become significant as
evidenced by the significant drop in the average coordination number of Si. By
contrast, Al-O tetrahedra remain free of NBO's and fully integrated in the
Al/Si-O network for all values of x. Calcium maintains a rather uniform
coordination sphere of approximately 5 oxygen atoms for all values of x. The
results suggest that not only Si/Al-O tetrahedra but Ca-O polyhedra, too, play
a role in determining the glassy structure
Cancer patientsâ experiences of using an Interactive Health Communication Application (IHCA)
Interactive Health Communication Applications (IHCAs) are increasingly used in health care. Studies document that IHCAs provide patients with knowledge and social support, enhance self- efficacy and can improve behavioural and clinical outcomes. However, research exploring patientsâ experiences of using IHCAs has been scarce. The aim of this study was to explore cancer patientsâ perspectives and experiences related to the use of an IHCA called WebChoice in their homes. Qualitative interviews were conducted with infrequent, medium and frequent IHCA usersâsix women and four men with breast and prostate cancer. The interviews were transcribed and analyzed inspired by interactionistic perspectives. We found that some patientsâ perceived WebChoice as a âfriend,â others as a âstranger.â Access to WebChoice stimulated particularly high frequency users to position themselves as âinformation seeking agents,â assuming an active patient role. However, to position oneself as an âactive patientâ was ambiguous and emotional. Feelings of âcalmnessâ, ânormalization of symptomsâ, feelings of âbeing part of a communityâ, feeling âupsetâ and âvulnerableâ, as well as âfeeling supportedâ were identified. Interaction with WebChoice implied for some users an increased focus on illness. Our findings indicate that the interaction between patients and an IHCA such as WebChoice occurs in a variety of ways, some of which are ambivalent or conflicting. Particularly for frequent and medium frequency users, it offers support, but may at the same time reinforce an element of uncertainty in their life. Such insights should be taken into consideration in the future development of IHCAs in healthcare in general and in particular for implementation into patientsâ private sphere
Promoter effect on the reduction behavior of wuestite-based catalysts for ammonia synthesis
Ammonia synthesis remains one of the most important catalytic processes since it enables efficient hydrogen storage and provides the basis for the production of fertilizers. Herein, complementary bulk and local analytical techniques were combined to investigate the effect of selected promoters (Al, K, Ca) on the reduction of wuestite into Îą-iron and their catalytic performance for ammonia synthesis. The use of promoters appears to have a positive effect on the wuestite-derived catalyst in ammonia synthesis. The promoters seemingly act as a binder for wuestite grains and impede the reduction and disproportionation events of wuestite precursors resulting in an increased catalytic performance. This effect is associated with an increase of surface area and mesoporosity. The study delivers new insights into the interplay of structure and promoters in wuestite-based catalysts
Infrared Echelle Spectroscopy of Palomar6 and M71
We present high-resolution infrared echelle spectroscopy for the globular
clusters Palomar 6 and M71. Our mean heliocentric radial velocity of Palomar 6
is +180.6 +/- 3.2 km sec/s and is 20 km/s lower than that found by Minniti in
1995. Contrary to the previous metallicity estimates using low-resolution
spectroscopy, our results show that Palomar~6 has an intermediate metallicity
with [Fe/H] = -1.0 +/- 0.1 and is slightly more metal-poor than M71. Reasonable
changes in the surface temperature or the microturbulent velocity of the model
atmospheres do not affect [Fe/H] at more than +/- 0.2 dex. In spite of its high
metallicity, based on the spectrum of a single cluster member the [Si/Fe] and
[Ti/Fe] ratios of Palomar~6 appear to be enhanced by 0.4 dex and 0.5 dex,
respectively, suggesting that the Galactic inner halo may have experienced a
very rapid chemical enrichment history.Comment: Accepted for publication in AJ (Nov. 2004
The C-type lectin receptor CLEC12A recognizes plasmodial hemozoin and contributes to cerebral malaria development
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