Establishment of Tall Fescue on West Louisiana Coastal Plain Soils (Bulletin #859)

Georgia-5 tall fescue was developed for use as a permanent, cool-season pasture grass on the Coastal Plain. The results of two field plot experiments and observations from additional small-plot plantings and 40 acres of pasture for grazing experiments at the Rosepine Research Station provide the basis for this discussion of Georgia-5 tall fescue establishment.https://digitalcommons.lsu.edu/agcenter_bulletins/1018/thumbnail.jp

Little Phillip No. 1 Bermudagrass (Research Information Sheet #106)

A unique, naturally occurring variety of Bermudagrass was identified in an Alicia Bermudagrass hay field in Sabine Parish in 1991. This publication includes information on the comparisons of this variety with the three Bermudagrass varieties most widely planted in the area in recent years, conducted in a field plot experiment at the Rosepine Research Station.https://digitalcommons.lsu.edu/agcenter_researchinfosheets/1006/thumbnail.jp

Establishing bundleflowers in bermuda and switchgrass

Last updated: 10/22/201

Eigen-analysis of Inviscid Fluid Structure Interaction (FSI) Systems with Complex Boundary Conditions

A method for extracting the eigenvalues and eigenmodes from complex coupled fluid-structure interaction (FSI) systems is presented. The FSI system under consideration in this case is a one-sided, inviscid flow over a finite-length compliant surface with complex boundary conditions, although the method could be applied to any FSI system. The flow is solved for the inviscid case using a boundary-element method solution of Laplace’s equation, while the finite compliant surface is solved through a finite-difference solution of the one-dimensional beam equation. The crux of the method lies in reducing the coupled fluid and structural equations down to a set of coupled linear differential equations. Standard Krylov subspace projection methods may then be used to determine the eigenvalues of the large system of linear equations. This method is applied to the analysis of hydroelastic FSI systems with complex boundary conditions that would be difficult or otherwise impossible to analyse using standard Galerkin methods. Specifically, the complex cases of inhomogeneous and discontinuous compliant wall properties and arbitrary hinge-joint conditions along the compliant surface are considered

Eigen-analysis of a Fully Viscous Boundary-Layer flow Interacting with a Finite Compliant Surface

A method and preliminary results are presented for the determination of eigenvalues and eigenmodes from fully viscous boundary layer flow interacting with a finite length one-sided compliant wall. This is an extension to the analysis of inviscid flow-structure systems which has been established in previous work. A combination of spectral and finite-difference methods are applied to a linear perturbation form of the full Navier-Stokes equations and one-dimensional beam equation. This yields a system of coupled linear equations that accurately define the spatio-temporal development of linear perturbations to a boundary layer flow over a finite-length compliant surface. Standard Krylov subspace projection methods are used to extract the eigenvalues from this complex system of equations. To date, the analysis of the development of Tollmien-Schlichting (TS) instabilities over a finite compliant surface have relied upon DNS-type results across a narrow (or even singular) spectrum of TS waves. The results from this method have the potential to describe conclusively the role that a finite length compliant surface has in the development of two-dimensional TS instabilities and other FSI instabilities across a broad spectrum

Dual random fragmentation and coagulation and an application to the genealogy of Yule processes

The purpose of this work is to describe a duality between a fragmentation associated to certain Dirichlet distributions and a natural random coagulation. The dual fragmentation and coalescent chains arising in this setting appear in the description of the genealogy of Yule processes.Comment: 14 page

Hydraulic flow through a channel contraction: multiple steady states

We have investigated shallow water flows through a channel with a contraction by experimental and theoretical means. The horizontal channel consists of a sluice gate and an upstream channel of constant width $b_0$ ending in a linear contraction of minimum width $b_c$. Experimentally, we observe upstream steady and moving bores/shocks, and oblique waves in the contraction, as single and multiple steady states, as well as a steady reservoir with a complex hydraulic jump in the contraction occurring in a small section of the $b_c/b_0$ and Froude number parameter plane. One-dimensional hydraulic theory provides a comprehensive leading-order approximation, in which a turbulent frictional parametrization is used to achieve quantitative agreement. An analytical and numerical analysis is given for two-dimensional supercritical shallow water flows. It shows that the one-dimensional hydraulic analysis for inviscid flows away from hydraulic jumps holds surprisingly well, even though the two-dimensional oblique hydraulic jump patterns can show large variations across the contraction channel

The experiences of people bereaved by suicide regarding the press reporting of the death: qualitative study

Background: Media guidelines on suicide reporting of suicide have two purposes: to prevent further suicides, and to minimise distress to the bereaved, who are themselves at increased risk of suicide. We aimed to describe the subjective experiences of people bereaved by suicide regarding media reporting of the suicide of their friend or relative. / Methods: We conducted a cross-sectional study of staff and students aged 18–40 at 37 United Kingdom higher educational institutions in 2010 to recruit adults who had experienced bereavement by the suicide of a close contact. We analysed free-text responses to a question probing experiences of the press after the suicide, using thematic analysis to identify key themes. / Results: We analysed responses from 140 eligible respondents, and identified 3 main themes: value placed on respecting the privacy or wishes of the bereaved; respect accorded to the deceased; and the role of the press in promoting suicide prevention messages. Many respondents described negative experiences of the press, with sub-themes capturing distressing experiences relating to perceptions of journalists’ intrusive behaviour, failure to consult appropriately with the bereaved, journalists releasing private information, negatively misrepresenting the deceased, and breaching the anonymity of the deceased or bereaved. We identified considerable variation in people’s views over acceptable levels of detail reported in the press, and in some cases objections were in relation to journalists following media guidelines. These divergent views illustrate the tensions between the twin purposes of media guidelines: to prevent further suicides, and to protect the bereaved. / Conclusions: The findings from our British sample provide journalists with personal perspectives from bereaved relatives on the impact of media intrusion, speculation, and misrepresentation, and an insight into disparate views on the nature of information relatives feel comfortable disclosing. These findings suggest a need for journalists’ training to include exposure to such views, to heighten awareness of potentially distressing effects and the nuances of bereaved people’s preferences. This should aim to encourage journalists to consult with bereaved relatives more sensitively, whilst also remaining mindful of media guidelines on the reporting of suicide

Bessel bridges decomposition with varying dimension. Applications to finance

We consider a class of stochastic processes containing the classical and well-studied class of Squared Bessel processes. Our model, however, allows the dimension be a function of the time. We first give some classical results in a larger context where a time-varying drift term can be added. Then in the non-drifted case we extend many results already proven in the case of classical Bessel processes to our context. Our deepest result is a decomposition of the Bridge process associated to this generalized squared Bessel process, much similar to the much celebrated result of J. Pitman and M. Yor. On a more practical point of view, we give a methodology to compute the Laplace transform of additive functionals of our process and the associated bridge. This permits in particular to get directly access to the joint distribution of the value at t of the process and its integral. We finally give some financial applications to illustrate the panel of applications of our results

Mean-field methods in evolutionary duplication-innovation-loss models for the genome-level repertoire of protein domains

We present a combined mean-field and simulation approach to different models describing the dynamics of classes formed by elements that can appear, disappear or copy themselves. These models, related to a paradigm duplication-innovation model known as Chinese Restaurant Process, are devised to reproduce the scaling behavior observed in the genome-wide repertoire of protein domains of all known species. In view of these data, we discuss the qualitative and quantitative differences of the alternative model formulations, focusing in particular on the roles of element loss and of the specificity of empirical domain classes.Comment: 10 Figures, 2 Table