450 research outputs found

    Information Flow through a Chaotic Channel: Prediction and Postdiction at Finite Resolution

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    We reconsider the persistence of information under the dynamics of the logistic map in order to discuss communication through a nonlinear channel where the sender can set the initial state of the system with finite resolution, and the recipient measures it with the same accuracy. We separate out the contributions of global phase space shrinkage and local phase space contraction and expansion to the uncertainty in predicting and postdicting the state of the system. Thus, we determine how the amplification parameter, the time lag, and the resolution influence the possibility for communication. A novel representation for real numbers is introduced that allows for a visualization of the flow of information between scales.Comment: 14 pages, 13 figure

    Phase diagram for morphological transitions of wetting films on chemically structured substrates

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    Using an interface displacement model we calculate the shapes of thin liquidlike films adsorbed on flat substrates containing a chemical stripe. We determine the entire phase diagram of morphological phase transitions in these films as function of temperature, undersaturation, and stripe widthComment: 15 pages, RevTeX, 7 Figure

    Shapes, contact angles, and line tensions of droplets on cylinders

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    Using an interface displacement model we calculate the shapes of nanometer-size liquid droplets on homogeneous cylindrical surfaces. We determine effective contact angles and line tensions, the latter defined as excess free energies per unit length associated with the two contact lines at the ends of the droplet. The dependences of these quantities on the cylinder radius and on the volume of the droplets are analyzed.Comment: 26 pages, RevTeX, 10 Figure

    Using Variable and Fixed Topological Indices for the Prediction of Reaction Rate Constants of Volatile Unsaturated Hydrocarbons with OH Radicals

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    mVolatile organic compounds (VOCs) play an important role in differentphotochemical processes in the troposphere. In order to predict their impact on ozoneformation processes a detailed knowledge about their abundance in the atmosphere as wellas their reaction rate constants is required. The QSPR models were developed for theprediction of reaction rate constants of volatile unsaturated hydrocarbons. The chemicalstructure was encoded by constitutional and topological indices. Multiple linear regressionmodels using CODESSA software was developed with the RMSCV error of 0.119 log units.The chemical structure was encoded by six topological indices. Additionally, a regressionmodel using a variable connectivity index was developed. It provided worse cross-validation results with an RMSCV error of 0.16 log units, but enabled a structuralinterpretation of the obtained model. We differentiated between three classes of carbonatoms: sp2-hybridized, non-allylic sp3-hybridized and allylic sp3-hybridized. The structuralinterpretation of the developed model shows that most probably the most importantmechanisms are the addition to multiple bonds and the hydrogen atom abstraction at allylicsites

    Geometry-dependent electrostatics near contact lines

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    Long-ranged electrostatic interactions in electrolytes modify their contact angles on charged substrates in a scale and geometry dependent manner. For angles measured at scales smaller than the typical Debye screening length, the wetting geometry near the contact line must be explicitly considered. Using variational and asymptotic methods, we derive new transcendental equations for the contact angle that depend on the electrostatic potential only at the three phase contact line. Analytic expressions are found in certain limits and compared with predictions for contact angles measured with lower resolution. An estimate for electrostatic contributions to {\it line} tension is also given.Comment: 3 .eps figures, 5p

    The Role of Magnetic Resonance Imaging and Positron Emission Tomography/Computed Tomography in the Primary Staging of Newly Diagnosed Prostate Cancer: A Systematic Review of the Literature

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    Context Management of newly diagnosed prostate cancer (PCa) is guided in part by accurate clinical staging. The role of imaging, including magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT), in initial staging remains controversial. Objective To systematically review the studies of MRI and/or PET/CT in the staging of newly diagnosed PCa with respect to tumor (T), nodal (N), and metastatic (M) staging (TNM staging). Evidence acquisition We performed a systematic review of the literature using MEDLINE and Web of Science databases between 2012 and 2020 following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement guidelines. Evidence synthesis A total of 139 studies (83 on T, 47 on N, and 24 on M status) were included. Ninety-nine (71%) were retrospective, 39 (28%) were prospective, and one was a randomized controlled trial (RCT). Most studies on T staging examined MRI, while PET/CT was used primarily for N and M staging. Sensitivity for the detection of extraprostatic extension, seminal vesicle invasion, or lymph node invasion ranged widely. When imaging was incorporated into existing risk tools, gain in accuracy was observed in some studies, although these findings have not been replicated. For M staging, most favorable results were reported for prostate-specific membrane antigen (PSMA) PET/CT, which demonstrated significantly better performance than conventional imaging. Conclusions A variety of studies on modern imaging techniques for TNM staging in newly diagnosed PCa exist. For T and N staging, reported sensitivity of imaging modalities such as MRI or PET/CT varied widely due to data heterogeneity, small sample size, and low event rates resulting in large confidence intervals and a high level of uncertainty. Therefore, uniformity in data presentation and standardization on this topic are needed. The most promising technique for M staging, which was evaluated recently in an RCT, is PSMA-PET/CT. Patient summary We performed a systematic review of currently available imaging modalities to stage newly diagnosed prostate cancer. With respect to local tumor and lymph node assessment, performance of imaging ranged widely. However, prostate-specific membrane antigen positron emission tomography/computed tomography showed favorable results for the detection of distant metastases

    Measuring Information Transfer

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    An information theoretic measure is derived that quantifies the statistical coherence between systems evolving in time. The standard time delayed mutual information fails to distinguish information that is actually exchanged from shared information due to common history and input signals. In our new approach, these influences are excluded by appropriate conditioning of transition probabilities. The resulting transfer entropy is able to distinguish driving and responding elements and to detect asymmetry in the coupling of subsystems.Comment: 4 pages, 4 Figures, Revte

    Denken over dieren : dier en ding, zegen en zorg

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    Dit rapport, dat in opdracht van het ministerie van Economische zaken, Landbouw en Innovatie is opgesteld, beschrijft een eerste trendanalyse (nulmeting) van (verwachte) morele opvattingen in Nederland over de omgang met dieren, nu en in de toekomst ten behoeve van het dierbeleid. In dit onderzoek is gestreefd naar de volgende inzichten: 1) de hedendaagse publieke opvattingen over de omgang met dieren; 2) de thema's die in de verschillende dierpraktijken spelen; 3) de verwachte ontwikkeling van deze thema's in de komende 20 jaar

    Study protocol to investigate the effect of a lifestyle intervention on body weight, psychological health status and risk factors associated with disease recurrence in women recovering from breast cancer treatment

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    Background Breast cancer survivors often encounter physiological and psychological problems related to their diagnosis and treatment that can influence long-term prognosis. The aim of this research is to investigate the effects of a lifestyle intervention on body weight and psychological well-being in women recovering from breast cancer treatment, and to determine the relationship between changes in these variables and biomarkers associated with disease recurrence and survival. Methods/design Following ethical approval, a total of 100 patients will be randomly assigned to a lifestyle intervention (incorporating dietary energy restriction in conjunction with aerobic exercise training) or normal care control group. Patients randomised to the dietary and exercise intervention will be given individualised healthy eating dietary advice and written information and attend moderate intensity aerobic exercise sessions on three to five days per week for a period of 24 weeks. The aim of this strategy is to induce a steady weight loss of up to 0.5 Kg each week. In addition, the overall quality of the diet will be examined with a view to (i) reducing the dietary intake of fat to ~25% of the total calories, (ii) eating at least 5 portions of fruit and vegetables a day, (iii) increasing the intake of fibre and reducing refined carbohydrates, and (iv) taking moderate amounts of alcohol. Outcome measures will include body weight and body composition, psychological health status (stress and depression), cardiorespiratory fitness and quality of life. In addition, biomarkers associated with disease recurrence, including stress hormones, estrogen status, inflammatory markers and indices of innate and adaptive immune function will be monitored. Discussion This research will provide valuable information on the effectiveness of a practical, easily implemented lifestyle intervention for evoking positive effects on body weight and psychological well-being, two important factors that can influence long-term prognosis in breast cancer survivors. However, the added value of the study is that it will also evaluate the effects of the lifestyle intervention on a range of biomarkers associated with disease recurrence and survival. Considered together, the results should improve our understanding of the potential role that lifestyle-modifiable factors could play in saving or prolonging lives

    Baddies in the classroom: media education and narrative writing

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    When teachers allow pupils to write stories that include elements of popular media, we must ask what to do with media once it has entered the classroom. This article relates findings from a classroom study which focuses on children’s media-based story writing. The study looks at children as producers of new media texts and describes their activities as a form of ‘media education’. The research shows that through their production of media-based stories, children are reflecting on their consumption of media. Furthermore, children’s media-based stories make explicit some of their implicit knowledge of new media forms. Finally, children’s stories provide ample opportunities for teachers to engage in important discussions about media within the framework of existing writing programmes
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