312 research outputs found
The responses of central octavolateralis cells to moving sources
Müller HM, Fleck A, Bleckmann H. The responses of central octavolateralis cells to moving sources. Journal of Comparative Physiology A. 1996;179:455-471
Rang und Recht:zur juristischen Austragung von Rangkonflikten im 17. und 18. Jahrhundert
Die Arbeit widmet sich Rangkonflikten, die während des späten 17. und frühen 18. Jahrhunderts ausgetragen wurden, wobei Ursachen, Verlauf, beteiligte soziale Gruppen und Ausgang der Auseinandersetzungen sowie Zusammenhänge zwischen Rangkonflikten und der Differenzierung der gesellschaftlichen Ordnung untersucht werden. Weiterhin wird der Frage nachgegangen, inwieweit die Lösung von Rangkonflikten dem allgemeinen Vorgang der Verrechtlichung folgte. Hierzu wird zunächst die Rechtsgrundlage für das Rangrecht, das "Ius praecedentiae", in den Blick genommen. Im zweiten Kapitel werden Rangkonflikte untersucht, die vor die universitären Spruchkollegien gelangten. Das dritte Kapitel behandelt Suppliken und Resolutionen in Rangkonflikten im Herzogtum Braunschweig-Wolfenbüttel. Schließlich wird die eingangs gestellte Frage nach der Verrechtlichung von Rangkonflikten erneut aufgegriffen und vor dem Hintergrund des Vergleichs zwischen Konsilien und Suppliken zu beantworten versucht
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Measuring flow velocity and flow direction by spatial and temporal analysis of flow fluctuations
If exposed to bulk water flow, fish lateral line afferents respond only to flow fluctuations (AC) and not to the steady (DC) component of the flow. Consequently, a single lateral line afferent can encode neither bulk flow direction nor velocity. It is possible, however, for a fish to obtain bulk flow information using multiple afferents that respond only to flow fluctuations. We show by means of particle image velocimetry that, if a flow contains fluctuations, these fluctuations propagate with the flow. A cross-correlation of water motion measured at an upstream point with that at a downstream point can then provide information about flow velocity and flow direction. In this study, we recorded from pairs of primary lateral line afferents while a fish was exposed to either bulk water flow, or to the water motion caused by a moving object. We confirm that lateral line afferents responded to the flow fluctuations and not to the DC component of the flow, and that responses of many fiber pairs were highly correlated, if they were time-shifted to correct for gross flow velocity and gross flow direction. To prove that a cross-correlation mechanism can be used to retrieve the information about gross flow velocity and direction, we measured the flow-induced bending motions of two flexible micropillars separated in a downstream direction. A cross-correlation of the bending motions of these micropillars did indeed produce an accurate estimate of the velocity vector along the direction of the micropillars
The BCL9-2 proto-oncogene governs estrogen receptor alpha expression in breast tumorigenesis
The majority of human breast cancers express estrogen receptor {Alpha} (ER), which is important for therapy with anti-estrogens. Here we describe the role of BCL9-2, a proto-oncogene previously characterized as co-activator of Wnt/{beta}-catenin signaling, for mammary tumorigenesis in mice and human. ER positive human breast cancers showed overexpression of BCL9-2 and tamoxifen treated patients with high BCL9-2 demonstrated a better survival. BCL9-2 was upregulated during puberty and pregnancy in normal mammary epithelia, but downregulated in the involuted gland. BCL9-2 overexpression in vivo delayed the mammary involution and induced alveolar hyperplasia. Moreover, aged BCL9-2 transgenic mice developed ductal-like mammary tumors with high nuclear ER expression. We found, that primary cell cultures of BCL9-2 breast tumors responded to tamoxifen treatment. Moreover, BCL9-2 regulated the expression of ER and the proliferation of human breast cancer cells independently of {beta}-catenin. Finally, we describe a novel mechanism, how BCL9-2 regulates ER transcription by interaction with Sp1 through the proximal ESR1 gene promoter. In summary, BCL9-2 induces ER positive breast cancers in vivo, regulates ER expression by a novel {beta}-catenin independent mechanism in breast cancer cells, and might predict the therapy response to tamoxifen treatment
Hydrodynamic object recognition using pressure sensing
Hydrodynamic sensing is instrumental to fish and some amphibians. It also represents, for underwater vehicles, an alternative way of sensing the fluid environment when visual and acoustic sensing are limited. To assess the effectiveness of hydrodynamic sensing and gain insight into its capabilities and limitations, we investigated the forward and inverse problem of detection and identification, using the hydrodynamic pressure in the neighbourhood, of a stationary obstacle described using a general shape representation. Based on conformal mapping and a general normalization procedure, our obstacle representation accounts for all specific features of progressive perceptual hydrodynamic imaging reported experimentally. Size, location and shape are encoded separately. The shape representation rests upon an asymptotic series which embodies the progressive character of hydrodynamic imaging through pressure sensing. A dynamic filtering method is used to invert noisy nonlinear pressure signals for the shape parameters. The results highlight the dependence of the sensitivity of hydrodynamic sensing not only on the relative distance to the disturbance but also its bearing
Unintended Consequences: Potential Downsides of the Air Force\u27s Conversion to Biofuels
The desire to reduce US dependence on foreign energy, ongoing environmental concerns, and the rising cost of petroleum have sparked significant development of greener alternative and renewable energy sources such as alcohol-based biofuels. To address these issues, the Department of Defense DOD has moved to diminish its reliance on petroleum for fueling aircraft and ground equipment. The US Air Force, in alignment with DOD objectives, has initiated several goals for reducing its use of energy: (1) decrease the use of petroleum-based fuel by 2 percent annually for the vehicle fleet, (2) increase the use of alternative fuel in motor vehicles annually by 10 percent, (3) certify all aircraft and weapon systems for a 5050 alternative fuel blend by 2011, and (4) have Air Force aircraft flying on 50 percent alternative fuel blends by 2016.1 This aggressive timetable moves the world s single largest petroleum consumer, the DOD, squarely into the alternative energies market. As the world s most prodigious fuel consumer, the DOD would likely drive segments of the aviation and motor fuels markets around the world to meet the demand for newly formulated alternative fuels and to convert existing fuel delivery systems to support the new market. Although conversion to alternative fuels can clearly lower the production of carbon dioxide, the risks that potential fuel spills pose to soil and groundwater are only now becoming clear
Prävention problematischer und suchtartiger Bildschirmmediennutzung: Eine deutschlandweite Befragung von Praxiseinrichtungen und Experten
Zweitveröffentlichung. Download von https://kfn.de/publikationen/kfn-forschungsbericht
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Interaction of barn owl leading edge serrations with freestream turbulence
The silent flight of barn owls is associated with wing and feather specialisations. Three special features are known: a serrated leading edge that is formed by free-standing barb tips which appears as a comb-like structure, a soft dorsal surface, and a fringed trailing edge. We used a model of the leading edge comb with 3D-curved serrations that was designed based on 3D micro-scans of rows of barbs from selected barn-owl feathers. The interaction of the flow with the serrations was measured with Particle-Image-Velocimetry in a flow channel at uniform steady inflow and was compared to the situation of inflow with freestream turbulence, generated from the turbulent wake of a cylinder placed upstream. In steady uniform flow, the serrations caused regular velocity streaks and a flow turning effect. When vortices of different size impacted the serrations, the serrations reduced the flow fluctuations downstream in each case, exemplified by a decreased root-mean-square value of the fluctuations in the wake of the serrations. This attenuation effect was stronger for the spanwise velocity component, leading to an overall flow homogenization. Our findings suggest that the serrations of the barn owl provide a passive flow control leading to reduced leading-edge noise when flying in turbulent environments
Methotrexate-associated toxicity in children with Down syndrome and acute lymphoblastic leukemia during consolidation therapy with high dose methotrexate according to ALL-BFM treatment regimen
Children with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) often suffer from severe toxicities during treatment, especially with high-dose methotrexate (HD-MTX). Systematic data on methotrexate (MTX) toxicity in these patients are rare. We analyzed seven MTX-associated toxicities during consolidation therapy in 103 DS- and 1,109 non-DS-patients (NDS) with ALL (NDS-ALL) enrolled in ALL-Berlin-Frankfurt-Münster (ALL-BFM) trials between 1995-2016 and 1995-2007, respectively. Patients received four courses MTX (5 g/m2 each) plus intrathecal MTX and 6-mercaptopurine (6-MP). From 2004 onwards, a dose of 0.5 g/m2 in the first MTX course has been recommended for DS-patients. DS-patients showed higher rates of grade 3/4 toxicities after the first course with 5 g/m2 MTX compared to NDS-patients (grade 3/4 toxicities 62 in 45 DS-patients vs 516 in 1,089 NDS-patients, P<0.001). The dose reduction (0.5 g/m2) in DS-patients has reduced toxicity (39 in 51 patients, P<0.001) without increasing the relapse risk (reduced dose, 5-year cumulative relapse incidence = 0.09±0.04 vs high dose, 0.10±0.05, P=0.51). MTX dose escalation to 1.0 g/m2 for DS-patients who tolerated 0.5 g/m2 (n= 28 of 51 patients) did not result in an increased rate of grade 3/4 toxicities after the second course (P=0.285). Differences in MTX plasma levels at 42 and 48 hours after the start of the first methotrexate infusion did not explain higher toxicity rates in DS-patients treated with 0.5 g/m2 compared to NDS-patients treated with 5 g/m2 Within the DS cohort a higher MTX plasma level was associated with increased toxicity. In conclusion, dose reduction in the first MTX course reduced severe toxicities without increasing the risk of relapse. (ClinicalTrials.gov identifier: NTC00430118, NCT01117441)
Field induced phases in UPt2Si2
The tetragonal compound UPt2Si2 has been characterised as a moderately mass
enhanced system with an antiferromagnetic ground state below T_N = 32 K. Here,
we present an extensive study of the behavior in high magnetic fields. We have
performed pulsed field magnetization and static field resistivity measurements
on single crystalline samples UPt2Si2. Along the crystallographic a axis, at
low temperatures, we find a metamagnetic-like transition in fields of the order
40 T, possibly indicating a first order transition. Along the crystallographic
c axis, in magnetic fields of B>= ~24 T, we find distinct anomalies in both
properties. From our analysis of the data we can distinguish new high field
phases above the AFM ground state. We discuss the emergence of these new phases
in the context of Fermi surface effects and the possible occurrence of a
Lifshitz or electronic topological transition, this in contrast to previous
modellings of UPt2Si2 based on crystal electric field effects.Comment: 10 pages, submitted to PR
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