Eigenvalue estimates for the Dirac operator depending on the Weyl curvature tensor

We prove new lower bounds for the first eigenvalue of the Dirac operator on compact manifolds whose Weyl tensor or curvature tensor, respectively, is divergence free. In the special case of Einstein manifolds, we obtain estimates depending on the Weyl tensor.Comment: Latex2.09, 9 page

Behaviour of adipose-derived canine mesenchymal stem cells after superparamagnetic iron oxide nanoparticles labelling for magnetic resonance imaging

Background: Therapy with mesenchymal stem cells (MSCs) has been reported to provide beneficial effects in the treatment of neurological and orthopaedic disorders in dogs. The exact mechanism of action is poorly understood. Magnetic resonance imaging (MRI) gives the opportunity to observe MSCs after clinical administration. To visualise MSCs with the help of MRI, labelling with an MRI contrast agent is necessary. However, it must be clarified whether there is any negative influence on cell function and viability after labelling prior to clinical administration. Results: For the purpose of the study, seven samples with canine adipose-derived stem cells were incubated with superparamagnetic iron oxide nanoparticles (SPIO: 319.2 µg/mL Fe) for 24 h. The internalisation of the iron particles occurred via endocytosis. SPIO particles were localized as free clusters in the cytoplasm or within lysosomes depending on the time of investigation. The efficiency of the labelling was investigated using Prussian blue staining and MACS assay. After 3 weeks the percentage of SPIO labelled canine stem cells decreased. Phalloidin staining showed no negative effect on the cytoskeleton. Labelled cells underwent osteogenic and adipogenic differentiation. Chondrogenic differentiation occurred to a lesser extent compared with a control sample. MTT-Test and wound healing assay showed no influence of labelling on the proliferation. The duration of SPIO labelling was assessed using a 1 Tesla clinical MRI scanner and T2 weighted turbo spin echo and T2 weighted gradient echo MRI sequences 1, 2 and 3 weeks after labelling. The hypointensity caused by SPIO lasted for 3 weeks in both sequences. Conclusions: An Endorem labelling concentration of 319.2 µg/mL Fe (448 µg/mL SPIO) had no adverse effects on the viability of canine ASCs. Therefore, this contrast agent could be used as a model for iron oxide labelling agents. However, the tracking ability in vivo has to be evaluated in further studies

Autômatos celulares com inércia

Resumo: Desde que os autômatos celulares (AC) foram criados, vêm sendo muito utilizados em diversas áreas de conhecimento, pois são sistemas simples e de fácil implementação computacional. Em geral, AC são compostos por redes de células, onde cada célula assume um valor numérico que determina seu estado. O tempo é discreto e o valor do estado de cada célula num tempo posterior depende do valor dos estados de seus vizinhos no tempo anterior. A exata conexão entre estas quantidades é estabelecida por uma regra dinâmica específica (a regra de atualização). Existem milhares de regras distintas para AC. Em nosso trabalho utilizaremos uma regra simples, onde o estado da célula no tempo t + 1 depende da soma dos estados de seus vizinhos no tempo t. Consideramos 3 estados, sendo 2 ativos (+1, -1), que competem dinamicamente, um passivo (zero), que não influencia a regra de mudança. Definimos também um “estado interno”, a inércia, que é um ingrediente novo no AC. Essa inércia (que pode variar de 0 ao número máximo de vizinhos) confere a cada célula uma resistência à mudança de seu estado. Discutimos então, no caso de um AC bidimensional, como a inércia modifica os padrões de evolução e as propriedades dinâmicas do sistema. Estudamos diferentes aspectos do problema, populações das configurações finais, tempos de convergência, dinâmica de invasão, geração de padrões espaciais, dinâmica da competição entre os estado ativos e assim por diante. De forma geral encontramos que a inércia pode alterar de forma bastante significativa a dinâmica e o comportamento médio típico de um mesmo AC

Killing the cMSSM softly

We investigate the constrained Minimal Supersymmetric Standard Model (cMSSM) in the light of constraining experimental and observational data from precision measurements, astrophysics, direct supersymmetry searches at the LHC and measurements of the properties of the Higgs boson, by means of a global fit using the program Fittino. As in previous studies, we find rather poor agreement of the best fit point with the global data. We also investigate the stability of the electro-weak vacuum in the preferred region of parameter space around the best fit point. We find that the vacuum is metastable, with a lifetime significantly longer than the age of the Universe. For the first time in a global fit of supersymmetry, we employ a consistent methodology to evaluate the goodness-of-fit of the cMSSM in a frequentist approach by deriving p-values from large sets of toy experiments. We analyse analytically and quantitatively the impact of the choice of the observable set on the p-value, and in particular its dilution when confronting the model with a large number of barely constraining measurements. Finally, for the preferred sets of observables, we obtain p-values for the cMSSM below 10%, i.e. we exclude the cMSSM as a model at the 90% confidence level.Comment: 22 pages, 16 figures, to be submitted to EPJ

Unusual infections: Femoral abscess due to Nocardia abscessus in a patient suffering from metastatic peripheral bronchial carcinoma and hygienic consequences

During the course of a peripheral bronchial carcinoma with pulmonary and cerebral metastases a femoral abscess developed in a 49 year-old patient after radio- and chemotherapy. A bacterial strain, which was isolated four times from a deep wound of the left thigh was tentatively identified as a member of the genus Nocardia on the basis of selected phenotypic and chemotaxonomic characteristics. The isolate was confirmed to belong to Nocardia abscessus by 16S rRNA gene sequencing. This species had previously been described as the causative agent of soft tissue infections. Although rare, nocardia soft tissue infections as complication of systemic nocardiosis are typical air born infections of immuncompromised patients and need specific attention. Infection prevention can be realized by restriction of soil and aerosol (builder's dust) together with antibiotic intervention (oral administration of trimethoprim/sulfamethoxazole)

Hybrid Attitude Control On-Board UWE-4 Using Magnetorquers and The Electric Propulsion System NanoFEEP

Orbit control on-board a 1U CubeSat was not demonstrated in orbit yet and is the technical goal of the UWE-4 mission. For this purpose, the electric propulsion system NanoFEEP was developed by our partners from TU Dresden. Four thruster heads are integrated into the rails of the CubeSat structure. This paper will give an insight into the first activation of an electric propulsion system on-board a 1U CubeSat on 26th February 2019. On the way to orbit control, attitude control capabilities have to be demonstrated in order to direct the thrust vector as desired. The calibration of the attitude determination sensors and first in-orbit attitude control experiments using the magnetorquers are described. We are able to measure the created torque of a thruster using the attitude determination sensors and can thus compute the created thrust. Finally, some lessons learned of the satellite design and operations of the UWE-4 satellite are discussed

Comparison of the endocranial- and brain volumes in brachycephalic dogs, mesaticephalic dogs and Cavalier King Charles spaniels in relation to their body weight

BACKGROUND: A number of studies have attempted to quantify the relative volumes of the endocranial volume and brain parenchyma in association with the pathogenesis of the Chiari-like malformation (CLM) in the Cavalier King Charles spaniel (CKCS). In our study we examine the influence of allometric scaling of the brain and cranial cavity volume on morphological parameters in different dog breeds. MRI scans of 110 dogs (35 mesaticephalic dogs, 35 brachycephalic dogs, 20 CKCSs with SM, and 20 CKCSs without SM) have been used to create 3-dimensional volumetric models of skull and brain parts. Volumes were related to body weight calculating the adjusted means for different breeds. RESULTS: There was a strong global dependency of all volumes to body weight (P<0.0001). The adjusted means of the absolute and relative volumes of brain parenchyma and cranial compartments are not significantly larger in CKCSs in comparison to brachycephalic and mesaticephalic dogs. A difference in absolute or relative volumes between CKCSs with and without SM after relating these values to body weight could not be identified. The relative volume of the hindbrain parenchyma (caudal fossa parenchyma percentage) was larger in brachycephalic dogs than in CKCSs, without causing herniation or SM. CONCLUSION: An influence of body weight exist in dogs, which can be sufficiently large to render conclusions on the difference in volumes of the brain and skull unsafe unless some account of the body weight is taken in the analysis. The results of this study challenge the role of overcrowding for the development of SM in dogs

Micro-rheological behaviour and nonlinear rheology of networks assembled from polysaccharides from the plant cell wall

The same fundamental questions that have driven enquiry into cytoskeletal mechanics can be asked of the considerably less-studied, yet arguably just as important, biopolymer matrix in the plant cell wall. In this case, it is well-known that polysaccharides, rather than filamentous and tubular protein assemblies, play a major role in satisfying the mechanical requirements of a successful cell wall, but developing a clear structure–function understanding has been exacerbated by the familiar issue of biological complexity. Herein, in the spirit of the mesoscopic approaches that have proved so illuminating in the study of cytoskeletal networks, the linear microrheological and strain-stiffening responses of biopolymeric networks reconstituted from pectin, a crucial cell wall polysaccharide, are examined. These are found to be well-captured by the glassy worm-like chain (GWLC) model of self-assembled semi-flexible filaments. Strikingly, the nonlinear mechanical response of these pectin networks is foun

A location aware mobile tourist guide selecting and interpreting sights and services by context matching

Most tourists exploring a destination either join a guided tour or walk on their own using maps. Neither are their individual preferences nor the actual situation considered. These tours are strongly inflexible. The ideal is an intelligent guide taking care of the whole tour organisation and execution in time. This is the main objective of the Dynamic Tour Guide (DTG). The DTG is a mobile agent that selects attractions, plans an individual tour, provides navigational guidance and offers location based interpretation. This kind of ambient intelligence is based on the analysis of all available context information to support the tourist in any possible way with the help of a mobile device