102 research outputs found
Die Rolle der globalen Kleinwaffendiffusion in Bezug auf innerstaatliche Konflikte: ErklÀrungsansÀtze und Herausforderungen
Mit einer gewissen Ăbertreibung, aber im Kern durchaus treffend, lieĂe sich das tödlichste Waffensystem zu Beginn des neuen Jahrtausends als mĂ€nnlich, unter achtzehn Jahre alt und ausgestattet mit einer Kalaschnikow beschreiben. Es sind Klein- und Leichtwaffen, die in erster Linie verantwortlich zeichnen fĂŒr die Opfer aktueller Konflikte, von denen SchĂ€tzungen zufolge 90 Prozent Zivilisten und keine Kombattanten im eigentlichen Sinne sind.2 Diese Waffen bestimmen maĂgeblich das AusmaĂ sowie den Verlauf gewalttĂ€tiger Auseinandersetzungen und ihr massenhafter Einsatz bzw. die daraus resultierenden negativen Folgen haben in jĂŒngster Vergangenheit die Agenda in Bezug auf Fragen der internationalen Sicherheit neu besetzt. Vor dem Hintergrund nationaler, regionaler und internationaler Bestrebungen zur Regulierung und Reduzierung der globalen Kleinwaffenströme, stellt die vorliegende Arbeit die komplexsymbiotische Beziehung zwischen Kleinwaffen und innerstaatlichen Konflikten in ihren unterschiedlichen ZusammenhĂ€ngen dar. Dabei bedeutet eine Zentrierung auf die âWerkzeuge der Gewaltâ eine neue Herangehensweise im Hinblick auf die Erforschung von Konfliktlagen. Die Arbeit gliedert sich in drei Teile: Der erste definiert die Begrifflichkeiten und stellt die Verbindung zwischen Kleinwaffen und Konflikt her. Im zweiten Teil, der in sich erneut zwei Ebenen unterscheidet, werden die verschiedenen Dimensionen der Kleinwaffenproblematik behandelt. Zum einen stehen die Diffusionsfaktoren im Mittelpunkt, mit einer Fokussierung auf die Angebotsseite, zum anderen die Mechanismen der Nachfrage. Anhand zweier Fallstudien erhalten die AusfĂŒhrungen zusĂ€tzliche Evidenz. Daran anknĂŒpfend enthĂ€lt der letzte Teil eine Diskussion der bisherigen HandlungsansĂ€tze und zukĂŒnftiger Herausforderungen im Hinblick auf eine EindĂ€mmung der Kleinwaffenverbreitung. Zu Lasten einer vertiefenden Darstellung einzelner Teilaspekte hat es sich diese Arbeit zur Aufgabe gestellt, die Problematik in ihrer gesamten KomplexitĂ€t zu veranschaulichen. Inhaltliche Reduzierungen sind demnach als Konzession an den Ăberblickscharakter der Arbeit zu verstehen. Dadurch wird deutlich, welche globale Bedeutung dem Handel und der Verbreitung von Klein- bzw Leichtwaffen im Hinblick auf Ursachen, Dynamiken und Transformationsmöglichkeiten gewalttĂ€tiger Konflikte zukommt.
âThe world is flooded with small arms and light weapons [...] They exacerbate conflict, spark refugee flows, undermine the rule of law, and spawn a culture of violence and impunity. In short, small arms are a threat to peace and development, to democracy and human rights.
Einleitung: Verbraucherbildung; Ein weiter Weg zum mĂŒndigen Verbraucher
Nicht erst der Beschluss der Kultusministerkonferenz zur Verbraucherbildung im Jahr 2013 hat dazu beigetragen, dass in vielen BundeslÀndern die Implementierung
von schulischer Verbraucherbildung angestrebt und zum Teil bereits
umgesetzt wird. Als Bildungsziel wird "mĂŒndige Verbraucher" genannt. Das bedeutet aber auch, nicht nur Kaufkompetenz zu vermitteln, sondern die ReflexionsfĂ€higkeit zu stĂ€rken
Cerebrospinal fluid promotes survival and astroglial differentiation of adult human neural progenitor cells but inhibits proliferation and neuronal differentiation
<p>Abstract</p> <p>Background</p> <p>Neural stem cells (NSCs) are a promising source for cell replacement therapies for neurological diseases. Growing evidence suggests an important role of cerebrospinal fluid (CSF) not only on neuroectodermal cells during brain development but also on the survival, proliferation and fate specification of NSCs in the adult brain. Existing <it>in vitro </it>studies focused on embryonic cell lines and embryonic CSF. We therefore studied the effects of adult human leptomeningeal CSF on the behaviour of adult human NSCs (ahNSCs).</p> <p>Results</p> <p>Adult CSF increased the survival rate of adult human NSCs compared to standard serum free culture media during both stem cell maintenance and differentiation. The presence of CSF promoted differentiation of NSCs leading to a faster loss of their self-renewal capacity as it is measured by the proliferation markers Ki67 and BrdU and stronger cell extension outgrowth with longer and more cell extensions per cell. After differentiation in CSF, we found a larger number of GFAP<sup>+ </sup>astroglial cells compared to differentiation in standard culture media and a lower number of ÎČ-tubulin III<sup>+ </sup>neuronal cells.</p> <p>Conclusions</p> <p>Our data demonstrate that adult human leptomeningeal CSF creates a beneficial environment for the survival and differentiation of adult human NSCs. Adult CSF is <it>in vitro </it>a strong glial differentiation stimulus and leads to a rapid loss of stem cell potential.</p
Seismic imaging of sandbox experiments â laboratory hardware setup and first reflection seismic sections
Abstract. With the study and technical development introduced here, we combine analogue sandbox simulation techniques with seismic physical modelling of sandbox models. For that purpose, we designed and developed a new mini-seismic facility for laboratory use, comprising a seismic tank, a PC-driven control unit, a positioning system, and piezo-electric transducers used here the first time in an array mode. To assess the possibilities and limits of seismic imaging of small-scale structures in sandbox models, different geometry setups were tested in the first experiments that also tested the proper functioning of the device and studied the seismo-elastic properties of the granular media used. Simple two-layer models of different materials and layer thicknesses as well as a more complex model comprising channels and shear zones were tested using different acquisition geometries and signal properties. We suggest using well sorted and well rounded grains with little surface roughness (glass beads). Source receiver-offsets less than 14 cm for imaging structures as small as 2.0â1.5 mm size have proven feasible. This is the best compromise between wide beam and high energy output, and being applicable with a consistent waveform. Resolution of the interfaces of layers of granular materials depends on the interface preparation rather than on the material itself. Flat grading of interfaces and powder coverage yields the clearest interface reflections. Finally, sandbox seismic sections provide images of very good quality showing constant thickness layers as well as predefined channel structures and fault traces from shear zones. Since these can be regarded in sandbox models as zones of decompaction, they behave as reflectors and can be imaged. The multiple-offset surveying introduced here improves the quality with respect to S/N-ratio and source signature even more; the maximum depth penetration in glass bead layers thereby amounts to 5 cm. Thus, the presented mini-seismic device is already able to resolve structures within simple models of saturated porous media, so that multiple-offset seismic imaging of shallow sandbox models, that are structurally evolving, is generally feasible.</jats:p
Duration of the parasitic phase determines subsequent performance in juvenile freshwater pearl mussels (Margaritifera margaritifera)
Hostâparasite systems have been useful in understanding coevolutionary patterns in sympatric species. Based on the exceptional interaction of the longâlived and highly hostâspecific freshwater pearl mussel (FPM; Margaritifera margaritifera) with its much shorterâlived host fish (Salmo trutta or Salmo salar), we tested the hypotheses that a longer duration of the parasitic phase increases fitnessârelated performance of mussels in their subsequent post parasitic phase, and that temperature is the main factor governing the duration of the parasitic phase. We collected juvenile mussels from naturally and artificially infested fish from eight rivers in Norway. Excysted juvenile mussels were maintained separately for each collection day, under similar temperature and food regimes, for up to 56 days. We recorded size at excystment, post excystment growth, and survival as indicators of juvenile fitness in relation to the duration of the parasitic phase. We also recorded the daily average temperatures for the entire excystment period. We observed strong positive relationships between the length of the parasitic phase and the post parasitic growth rate, size at excystment and post parasitic survival. Temperature was identified as an important factor governing excystment, with higher temperatures decreasing the duration of the parasitic phase. Our results indicate that juvenile mussels with the longest parasitic phase have better resources (larger size and better growth rate) to start their benthic developmental phase and therefore to survive their first winter. Consequently, the parasitic phase is crucial in determining subsequent survival. The temperature dependence of this interaction suggests that climate change may affect the sensitive relationship between endangered FPMs and their fish hosts.publishedVersio
Ontogeny of juvenile freshwater pearl mussels, Margaritifera margaritifera (Bivalvia: Margaritiferidae).
The gills of juvenile freshwater bivalves undergo a complex morphogenesis that may correlate with changes in feeding ecology, but ontogenic studies on juvenile mussels are rare. Scanning electron microscopy was used to examine the ultrastructure and ontogeny of 117 juvenile freshwater pearl mussels (Margaritifera margaritifera) ranging in age from 1â44 months and length from 0.49â8.90 mm. Three stages of gill development are described. In Stage 1 (5â9 inner demibranch filaments), only unreflected inner demibranch filaments were present. In Stage 2 (9â17 inner demibranch filaments), inner demibranch filaments began to reflect when shell length exceeded 1.13 mm, at 13â16 months old. Reflection began in medial filaments and then proceeded anterior and posterior. In Stage 3 (28â94 inner demibranch filaments), outer demibranch filaments began developing at shell length > 3.1 mm and about 34 months of age. The oral groove on the inner demibranch was first observed in 34 month old specimens > 2.66 mm but was never observed on the outer demibranch. Shell length (R2 = 0.99) was a better predictor of developmental stage compared to age (R2 = 0.84). The full suite of gill ciliation was present on filaments in all stages. Interfilamentary distance averaged 31.3 ÎŒm and did not change with age (4â44 months) or with size (0.75â8.9 mm). Distance between laterofrontal cirri couplets averaged 1.54 ÎŒm and did not change significantly with size or age. Labial palp primordia were present in even the youngest individuals but ciliature became more diverse in more developed individuals. Information presented here is valuable to captive rearing programmes as it provides insight in to when juveniles may be particularly vulnerable to stressors due to specific ontogenic changes. The data are compared with two other recent studies of Margaritifera development.N/
Fish and mussels: importance of fish for freshwater mussel conservation
Co-extinctions are increasingly recognized as one of the major processes leading to
the global biodiversity crisis, but there is still limited scientific evidence on the magnitude of potential impacts and causal mechanisms responsible for the decline of affiliate (dependent) species. Freshwater mussels (Bivalvia, Unionida), one of the most
threatened faunal groups on Earth, need to pass through a parasitic larval (glochidia)
phase using fishes as hosts to complete their life cycle. Here, we provide a synthesis
of published evidence on the fishâmussel relationship to explore possible patterns in
co-extinction risk and discuss the main threats affecting this interaction. We retrieved
205 publications until December 2015, most of which were performed in North
America, completed under laboratory conditions and were aimed at characterizing the
life cycle and/or determining the suitable fish hosts for freshwater mussels. Mussel
species were reported to infest between one and 53 fish species, with some fish families (e.g., Cyprinidae and Percidae) being used more often as hosts than others. No
relationship was found between the breadth of host use and the extinction risk of
freshwater mussels. Very few studies focused on threats affecting the fishâmussel
relationship, a knowledge gap that may impair the application of future conservation
measures. Here, we identify a variety of threats that may negatively affect fish species,
document and discuss the concomitant impacts on freshwater mussels, and suggest
directions for future studies.The Portuguese Foundation for Science and TechnologyâFCT through POPH/FSE funds supported VM, MI and MLL under grants (SFRH/BD/108298/2015), (SFRH/BPD/90088/2012), (SFRH/BD/115728/2016), respectively. KD acknowledges the support from the Czech Science Foundation (13-05872S). RS acknowledges the support of the strategic programme UID/BIA/04050/2013 (POCI-01-0145-
FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020-Programa Operacional Competitividade e Internacionalização (POCI). This study was conducted as part of the project FRESHCO: Multiple implications of invasive species on Freshwater Mussel co-extinction processes,
supported by FCT (contract: PTDC/AGRFOR/1627/2014)
Lateral frontal cortex volume reduction in Tourette syndrome revealed by VBM
<p>Abstract</p> <p>Background</p> <p>Structural changes have been found predominantly in the frontal cortex and in the striatum in children and adolescents with Gilles de la Tourette syndrome (GTS). The influence of comorbid symptomatology is unclear. Here we sought to address the question of gray matter abnormalities in GTS patients <it>with </it>co-morbid obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD) using voxel-based morphometry (VBM) in twenty-nine adult actually unmedicated GTS patients and twenty-five healthy control subjects.</p> <p>Results</p> <p>In GTS we detected a cluster of decreased gray matter volume in the left inferior frontal gyrus (IFG), but no regions demonstrating volume increases. By comparing subgroups of GTS with comorbid ADHD to the subgroup with comorbid OCD, we found a left-sided amygdalar volume increase.</p> <p>Conclusions</p> <p>From our results it is suggested that the left IFG may constitute a common underlying structural correlate of GTS with co-morbid OCD/ADHD. A volume reduction in this brain region that has been previously identified as a key region in OCD and was associated with the active inhibition of attentional processes may reflect the failure to control behavior. Amygdala volume increase is discussed on the background of a linkage of this structure with ADHD symptomatology. Correlations with clinical data revealed gray matter volume changes in specific brain areas that have been described in these conditions each.</p
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