Assessment of Watershed Model Simplification and Potential Application in Small Ungaged Watersheds: A Case Study of Big Creek, Atlanta, GA

Technological and methodological advances of the past few decades have provided hydrologists with advanced and increasingly complex hydrological models. These models improve our ability to simulate hydrological systems, but they also require a lot of detailed input data and, therefore, have a limited applicability in locations with poor data availability. From a case study of Big Creek watershed, a 186.4 km2 urbanizing watershed in Atlanta, GA, for which continuous flow data are available since 1960, this project investigates the relationship between model complexity, data availability and predictive performance in order to provide reliability factors for the use of reduced complexity models in areas with limited data availability, such as small ungaged watersheds in similar environments. My hope is to identify ways to increase model efficiency without sacrificing significant model reliability that will be transferable to ungaged watersheds

Nutritional management of individuals with Huntington’s disease: nutritional guidelines

The delivery of good nutritional care is a fundamental element of the management of individuals with Huntington’s disease and all patients with Huntington’s disease will, at some time, need dietary intervention because of the sequela of the disease; yet there are no European nutritional guidelines. The European Huntington’s Disease Network Standards of Care Dietitians Group has brought together expert dietitians from across Europe to produce nutritional guidelines to improve the nutritional management of individuals with Huntington’s disease. The guidelines were developed to promote optimal nutritional screening, assessment and management of individuals throughout all stages of the disease, with the aim of improving the standard of nutritional care delivered. Literature was systematically searched in an attempt to ensure that the recommendations are based on sound evidence and where evidence is lacking, specific guidance is based on consensus expert dietetic opinion. The provision of nutritional care varies widely between countries. Implementation of these nutritional guidelines across Europe should improve the quality of nutritional care delivered to individuals with Huntington’s disease

A nonlinear random walk approach to concentration-dependent contaminant transport in porous media

We propose a nonlinear random walk model to describe the dynamics of dense contaminant plumes in porous media. A coupling between concentration and velocity fields is found, so that transport displays non-Fickian features. The qualitative behavior of the pollutant spatial profiles and moments is explored with the help of Monte Carlo simulation, within a Continuous Time Random Walk approach. Model outcomes are then compared with experimental measurements of variable-density contaminant transport in homogeneous and saturated vertical columns.Comment: 8 pages, 9 figure

Cauchy's formulas for random walks in bounded domains

Cauchy's formula was originally established for random straight paths crossing a body $B \subset \mathbb{R}^{n}$ and basically relates the average chord length through $B$ to the ratio between the volume and the surface of the body itself. The original statement was later extended in the context of transport theory so as to cover the stochastic paths of Pearson random walks with exponentially distributed flight lengths traversing a bounded domain. Some heuristic arguments suggest that Cauchy's formula may also hold true for Pearson random walks with arbitrarily distributed flight lengths. For such a broad class of stochastic processes, we rigorously derive a generalized Cauchy's formula for the average length travelled by the walkers in the body, and show that this quantity depends indeed only on the ratio between the volume and the surface, provided that some constraints are imposed on the entrance step of the walker in $B$. Similar results are obtained also for the average number of collisions performed by the walker in $B$, and an extension to absorbing media is discussed.Comment: 12 pages, 6 figure

Ricostruzione e valutazione dello stato anteriore

Il 22% della popolazione anziana in Italia ha pi\uf9 di 65 anni, con un costo complessivo per le assicurazioni nel 2017 per i sinistri per macroinvalidit\ue0 e morte pari a 4,6 miliardi di euro. Si pone pertanto per il sistema sanitario nazionale e per i medici legali il problema di come valutare il danno biologico nella persona anziana. Infatti, le tabelle per la valutazione del danno a persona prendono in considerazione l\u2019entit\ue0 della lesione, ma non l\u2019et\ue0 del paziente. Si \ue8 deciso quindi di applicare per la prima volta alla medicina legale la metodologia della Consensus Conference, utilizzata generalmente per dirimere questioni controverse in ambito clinico, al fine di affrontare un tema di fondamentale interesse scientifico e produrre un unico documento contenente indicazioni per valutare in maniera metodologicamente corretta e condivisa il danno biologico nella persona anziana. Ad oggi la mancanza di una condivisione di opinioni su questo tema produce una forte disomogeneit\ue0 di comportamenti sul piano clinico e valutativo e il documento comporter\ue0 grandi ripercussioni sull\u2019attivit\ue0 quotidiana stante il costante invecchiamento della popolazione generale e le grandi problematiche che la fragilit\ue0 dell\u2019anziano crea nella valutazione del danno alla persona

Collision number statistics for transport processes

Many physical observables can be represented as a particle spending some random time within a given domain. For a broad class of transport-dominated processes, we detail how it is possible to express the moments of the number of particle collisions in an arbitrary volume in terms of repeated convolutions of the ensemble equilibrium distribution. This approach is shown to generalize the celebrated Kac formula for the moments of residence times, which is recovered in the diffusion limit. Some practical applications are illustrated for bounded, unbounded and absorbing domains.Comment: 4 pages, 4 figure

Discrete Feynman-Kac formulas for branching random walks

Branching random walks are key to the description of several physical and biological systems, such as neutron multiplication, genetics and population dynamics. For a broad class of such processes, in this Letter we derive the discrete Feynman-Kac equations for the probability and the moments of the number of visits $n_V$ of the walker to a given region $V$ in the phase space. Feynman-Kac formulas for the residence times of Markovian processes are recovered in the diffusion limit.Comment: 4 pages, 3 figure