238 research outputs found

    Asymptotic analysis for Korteweg models

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    This paper deals with a sharp interface limit of the isothermal Navier-Stokes-Korteweg system. The sharp interface limit is performed by matched asymptotic expansions of the fields in powers of the interface width. These expansions are considered in the interfacial region (inner expansions) and in the bulk (outer expansion) and are matched order by order. Particularly we consider the first orders of the corresponding inner equations obtained by a change of coordinates in an interfacial layer. For a specific scaling we establish solvability criteria for these inner equations and recover the results within the general setting of jump conditions for sharp interface models

    Comparison of data-driven uncertainty quantification methods for a carbon dioxide storage benchmark scenario

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    A variety of methods is available to quantify uncertainties arising with\-in the modeling of flow and transport in carbon dioxide storage, but there is a lack of thorough comparisons. Usually, raw data from such storage sites can hardly be described by theoretical statistical distributions since only very limited data is available. Hence, exact information on distribution shapes for all uncertain parameters is very rare in realistic applications. We discuss and compare four different methods tested for data-driven uncertainty quantification based on a benchmark scenario of carbon dioxide storage. In the benchmark, for which we provide data and code, carbon dioxide is injected into a saline aquifer modeled by the nonlinear capillarity-free fractional flow formulation for two incompressible fluid phases, namely carbon dioxide and brine. To cover different aspects of uncertainty quantification, we incorporate various sources of uncertainty such as uncertainty of boundary conditions, of conceptual model definitions and of material properties. We consider recent versions of the following non-intrusive and intrusive uncertainty quantification methods: arbitary polynomial chaos, spatially adaptive sparse grids, kernel-based greedy interpolation and hybrid stochastic Galerkin. The performance of each approach is demonstrated assessing expectation value and standard deviation of the carbon dioxide saturation against a reference statistic based on Monte Carlo sampling. We compare the convergence of all methods reporting on accuracy with respect to the number of model runs and resolution. Finally we offer suggestions about the methods' advantages and disadvantages that can guide the modeler for uncertainty quantification in carbon dioxide storage and beyond

    Spectral structure and decompositions of optical states, and their applications

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    We discuss the spectral structure and decomposition of multi-photon states. Ordinarily `multi-photon states' and `Fock states' are regarded as synonymous. However, when the spectral degrees of freedom are included this is not the case, and the class of `multi-photon' states is much broader than the class of `Fock' states. We discuss the criteria for a state to be considered a Fock state. We then address the decomposition of general multi-photon states into bases of orthogonal eigenmodes, building on existing multi-mode theory, and introduce an occupation number representation that provides an elegant description of such states that in many situations simplifies calculations. Finally we apply this technique to several example situations, which are highly relevant for state of the art experiments. These include Hong-Ou-Mandel interference, spectral filtering, finite bandwidth photo-detection, homodyne detection and the conditional preparation of Schr\"odinger Kitten and Fock states. Our techniques allow for very simple descriptions of each of these examples.Comment: 12 page

    German validation of Quality of Life after Brain Injury (QOLIBRI) assessment and associated factors

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    The consequences of traumatic brain injury (TBI) for health-related quality of life (HRQoL) are still poorly understood, and no TBI-specific instrument has hitherto been available. This paper describes in detail the psychometrics and validity of the German version of an internationally developed, self-rated HRQoL tool after TBI—the QOLIBRI (Quality of Life after Brain Injury). Factors associated with HRQoL, such as the impact of cognitive status and awareness, are specifically reported. One-hundred seventy-two participants after TBI were recruited from the records of acute clinics, most of whom having a Glasgow Coma Scale (GCS) 24-hour worst score and a Glasgow Outcome Scale (GOSE) score. Participants had severe (24%), moderate (11%) and mild (56%) injuries as assessed on the GCS, 3 months to 15 years post-injury. The QOLIBRI uses 37 items to measure “satisfaction” in the areas of “Cognition”, “Self”, “Daily Life and Autonomy”, and “Social Relationships”, and “feeling bothered” by “Emotions”and “Physical Problems”. The scales meet standard psychometric criteria (α = .84 to .96; intra-class correlation—ICC = .72 to .91). ICCs (0.68 to 0.90) and αs (.83 to .96) were also good in a subgroup of participants with lower cognitive performance. The six-subscale structure of the international sample was reproduced for the German version using confirmatory factor analyses and Rasch analysis. Scale validity was supported by systematic relationships observed between the QOLIBRI and the GOSE, Patient Competency Rating Scale for Neurorehabilitation (PCRS-NR), Hospital Anxiety and Depression Scale (HADS), Profile of Mood States (POMS), Short Form 36 (SF-36), and Satisfaction with Life Scale (SWLS). The German QOLIBRI contains novel information not provided by other currently available measures and has good psychometric criteria. It is potentially useful for clinicians and researchers, in post-acute and rehabilitation studies, on a group and individual level.Additional co-authors: Klaus von Wild and Henning Gibbon

    Expression of Olig2, Nestin, NogoA and AQP4 have no impact on overall survival in IDH- wildtype glioblastoma

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    Despite many years of research efforts and clinical trials the prognosis of patients diagnosed with glioblastoma remains very poor. The oligodendrocyte transcription factor 2 (Olig2) was identified as a marker for glioma stem cells, which are believed to be responsible for glioma recurrence and therapy resistance. In this retrospective analysis we assessed the prognos- tic value of oligodendroglial and glioma stem cell markers in 113 IDH-wildtype glioblasto- mas. Immunohistochemical staining for Olig2, NogoA, AQP4 and Nestin was performed in combination with sequencing of IDH1 and IDH2 as well as promotor methylation analysis of the MGMT gene. Even though differences in overall survival according to Olig2 expression were observed, univariate and multivariate survival analysis did not reveal a firm significant prognostic impact of Olig2, NogoA, AQP4 or Nestin expression. Additionally, no differences in the expression of these markers depending on clinical status, age or gender were found. The established independent prognostic factors age = 70 and methylated MGMT gene promoter were significant in the multivariate analysis. In conclusion expression of oligodendroglial and glioma stem cell markers do not have an inde- pendent prognostic effect in IDH-wildtype glioblastoma.German Research Foundation/[]/DGF/AlemaniaPublication Fund of Hannover Medical School/[]/MHH/AlemaniaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN

    Estimación de la variabilidad genética entre ecotipos de cocoteros presentes en cuba por istr

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    Se realizó la caracterización molecular entre 16 ecotipos de cocoteros pertenecientes a una población del municipio de Baracoa, provincia Guantánamo, empleando la técnica Inverse Sequence Tagged Repeat (ISTR detectó un polimorfismo del 81,8%, demostrando la potencialidad de este marcador para realizar estudios de diversidad molecular en el cocotero. El porcentaje de identificación fue alto (Pi=91,2%), lo cual sugiere que las combinaciones de oligonucleótidos empleadas pudieran ser utilizada para estudios de identificación de ecotipos en poblaciones de cocotero de la zona de Baracoa mientras, que la heterocigocidad esperada fue baja (He=0,30). La evaluación de la diversidad en los diferentes ecotipos de cocoteros mediante marcadores ISTR mostró que se cuenta con un nivel de variabilidad, atendiendo a los grupos formados, lo que se corresponde con la gran variación morfológica observada en la población in situ. Además, estos resultados sugieren que la hibridación natural ha sido un factor determinante en la generación de la variabilidad encontrada entre los ecotipos, característica de las variedades de cocotero

    Clinical relevance of molecular characteristics in Burkitt lymphoma differs according to age

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    While survival has improved for Burkitt lymphoma patients, potential differences in outcome between pediatric and adult patients remain unclear. In both age groups, survival remains poor at relapse. Therefore, we conducted a comparative study in a large pediatric cohort, including 191 cases and 97 samples from adults. While TP53 and CCND3 mutation frequencies are not age related, samples from pediatric patients showed a higher frequency of mutations in ID3, DDX3X, ARID1A and SMARCA4, while several genes such as BCL2 and YY1AP1 are almost exclusively mutated in adult patients. An unbiased analysis reveals a transition of the mutational profile between 25 and 40 years of age. Survival analysis in the pediatric cohort confirms that TP53 mutations are significantly associated with higher incidence of relapse (25 ± 4% versus 6 ± 2%, p-value 0.0002). This identifies a promising molecular marker for relapse incidence in pediatric BL which will be used in future clinical trials

    3D Game World in OpenGL

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    Tato práce se zabývá studiem moderních technik v počítačové grafice; návrhem a vytvořením aplikace, jež může sloužit jako jádro budoucímu hernímu enginu. V práci jsou vyzdviženy techniky tvorby rozsáhlých terénů, pokročilých stínů, generování fyzikálně založené oblohy a vykreslování velkého množství objektů. Závěrem je provedeno výkonnostní testování těchto modulů.Focus of this master's thesis is a study of modern techniques in computer graphics and designing and developing custom application based on which could be developed new game engine. In this thesis are highlighted techniques for creating large terrains, advanced shadows, physically based sky rendering and drawing large set of objects. Finally, performance testing of these modules is performed.
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