741 research outputs found

    Strain-Rate Frequency Superposition (SRFS) - A rheological probe of structural relaxation in soft materials

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    The rheological properties of soft materials often exhibit surprisingly universal linear and non-linear features. Here we show that these properties can be unified by considering the effect of the strain-rate amplitude on the structural relaxation of the material. We present a new form of oscillatory rheology, Strain-Rate Frequency Superposition (SRFS), where the strain-rate amplitude is fixed as the frequency is varied. We show that SRFS can isolate the response due to structural relaxation, even when it occurs at frequencies too low to be accessible with standard techniques.Comment: 4 pages, 4 figure

    Hydrologic modelling of New England River basins using radar rainfall data

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1988.Bibliography: p. 157-164.by Jonathan David Wyss.Ph.D

    Adaptive data-driven selection of sequences of biological and cognitive markers in pre-clinical diagnosis of dementia.

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    Effective clinical decision procedures must balance multiple competing objectives such as time-to-decision, acquisition costs, and accuracy. We describe and evaluate POSEIDON, a data-driven method for PrOspective SEquentIal DiagnOsis with Neutral zones to individualize clinical classifications. We evaluated the framework with an application in which the algorithm sequentially proposes to include cognitive, imaging, or molecular markers if a sufficiently more accurate prognosis of clinical decline to manifest Alzheimer's disease is expected. Over a wide range of cost parameter data-driven tuning lead to quantitatively lower total cost compared to ad hoc fixed sets of measurements. The classification accuracy based on all longitudinal data from participants that was acquired over 4.8 years on average was 0.89. The sequential algorithm selected 14 percent of available measurements and concluded after an average follow-up time of 0.74 years at the expense of 0.05 lower accuracy. Sequential classifiers were competitive from a multi-objective perspective since they could dominate fixed sets of measurements by making fewer errors using less resources. Nevertheless, the trade-off of competing objectives depends on inherently subjective prescribed cost parameters. Thus, despite the effectiveness of the method, the implementation into consequential clinical applications will remain controversial and evolve around the choice of cost parameters

    Ketogenic diet effects on inflammatory allodynia and ongoing pain in rodents

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    © 2021, The Author(s). Ketogenic diets are very low carbohydrate, high fat, moderate protein diets used to treat medication-resistant epilepsy. Growing evidence suggests that one of the ketogenic diet’s main mechanisms of action is reducing inflammation. Here, we examined the diet’s effects on experimental inflammatory pain in rodent models. Young adult rats and mice were placed on the ketogenic diet or maintained on control diet. After 3–4 weeks on their respective diets, complete Freund’s adjuvant (CFA) was injected in one hindpaw to induce inflammation; the contralateral paw was used as the control. Tactile sensitivity (von Frey) and indicators of spontaneous pain were quantified before and after CFA injection. Ketogenic diet treatment significantly reduced tactile allodynia in both rats and mice, though with a species-specific time course. There was a strong trend to reduced spontaneous pain in rats but not mice. These data suggest that ketogenic diets or other ketogenic treatments might be useful treatments for conditions involving inflammatory pain

    Konstruktion und Durchführung eines Video-Portfolios

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    In diesem Werkstattbericht wird die Konstruktion und Durchführung einer schulpraktischen Abschlussprüfung in Form eines Video-Portfolios beschrieben. Im Rahmen dieser Prüfung reichen die Studierenden die Planung einer Lektion, ein Video der Umsetzung dieser Lektion sowie schriftliche Analysen der videografierten Lektion ein. Die Studierenden haben Zugang zu den Beurteilungskriterien, zu Geräten und zu einem Online-Kurs, der Hinweise zum Videografieren und zur schriftlichen Umsetzung bietet. Das Video-Portfolio wird von zwei Expert*innen unabhängig voneinander beurteilt. Nach dem Noteneintrag werden alle personenbezogenen Daten gelöscht und die Studierenden erhalten einen Evaluationsfragebogen

    The use of an artificial nucleotide for polymerase-based recognition of carcinogenic O6-alkylguanine DNA adducts.

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    Enzymatic approaches for locating alkylation adducts at single-base resolution in DNA could enable new technologies for understanding carcinogenesis and supporting personalized chemotherapy. Artificial nucleotides that specifically pair with alkylated bases offer a possible strategy for recognition and amplification of adducted DNA, and adduct-templated incorporation of an artificial nucleotide has been demonstrated for a model DNA adduct O(6)-benzylguanine by a DNA polymerase. In this study, DNA adducts of biological relevance, O(6)-methylguanine (O(6)-MeG) and O(6)-carboxymethylguanine (O(6)-CMG), were characterized to be effective templates for the incorporation of benzimidazole-derived 2'-deoxynucleoside-5'-O-triphosphates ( BENZI: TP and BIM: TP) by an engineered KlenTaq DNA polymerase. The enzyme catalyzed specific incorporation of the artificial nucleotide BENZI: opposite adducts, with up to 150-fold higher catalytic efficiency for O(6)-MeG over guanine in the template. Furthermore, addition of artificial nucleotide BENZI: was required for full-length DNA synthesis during bypass of O(6)-CMG. Selective incorporation of the artificial nucleotide opposite an O(6)-alkylguanine DNA adduct was verified using a novel 2',3'-dideoxy derivative of BENZI: TP. The strategy was used to recognize adducts in the presence of excess unmodified DNA. The specific processing of BENZI: TP opposite biologically relevant O(6)-alkylguanine adducts is characterized herein as a basis for potential future DNA adduct sequencing technologies

    Analysekompetenz von Studierenden mit einem Video-Portfolio beurteilen

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    Die Autor*innen überprüfen die inhaltliche und ökologische Validität eines benoteten Video-Portfolios als – je nach Lesart – Ersatz (Verlust) beziehungsweise Weiterentwicklung der über Jahrzehnte eingesetzten Lehrprobe oder Prüfungslektion. Insgesamt findet sich eine hohe inhaltliche und eine mittlere ökologische Validität, was derartige Evaluationen zu einem wirksamen Instrument der Weiterentwicklung von Prüfungen macht. (DIPF/Orig.

    Capillary micromechanics: Measuring the elasticity of microscopic soft objects

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    We present a simple method for accessing the elastic properties of microscopic deformable particles. This method is based on measuring the pressure-induced deformation of soft particles as they are forced through a tapered glass microcapillary. It allows us to determine both the compressive and the shear modulus of a deformable object in one single experiment. Measurements on a model system of poly-acrylamide microgel particles exhibit excellent agreement with measurements on bulk gels of identical composition. Our approach is applicable over a wide range of mechanical properties and should thus be a valuable tool for the characterization of a variety of soft and biological materials

    Eisman and Warrack Standard & Poor\u27s Structured Finance Teleconference Transcript

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    Transcript of Standard & Poor\u27s Structured Finance meeting/conference call discussing its press release issued that same morning announcing that it placed 612 subprime RMBS classes on Credit Watch Negative
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