Detailed simulations of cell biology with Smoldyn 2.1.

Most cellular processes depend on intracellular locations and random collisions of individual protein molecules. To model these processes, we developed algorithms to simulate the diffusion, membrane interactions, and reactions of individual molecules, and implemented these in the Smoldyn program. Compared to the popular MCell and ChemCell simulators, we found that Smoldyn was in many cases more accurate, more computationally efficient, and easier to use. Using Smoldyn, we modeled pheromone response system signaling among yeast cells of opposite mating type. This model showed that secreted Bar1 protease might help a cell identify the fittest mating partner by sharpening the pheromone concentration gradient. This model involved about 200,000 protein molecules, about 7000 cubic microns of volume, and about 75 minutes of simulated time; it took about 10 hours to run. Over the next several years, as faster computers become available, Smoldyn will allow researchers to model and explore systems the size of entire bacterial and smaller eukaryotic cells

The Role of Underemployment in Employee’s Overall Job Satisfaction: The Alabama Case.

Job satisfaction is an important measure of utility that employees derive from their jobs and is related to various features of the job such as pay, security, intrinsic values of work, working conditions, career growth opportunities, working hours, and the like. This paper analyzes the relationship between underemployment and overall job satisfaction among other personal and job characteristics of the workforce in Alabama using survey data from Alabama workforce development regions. A logistic model is used to analyze the determinants of job satisfaction in Alabama including underemployment. Estimation results show a negative relationship between underemployment and job satisfaction. Personal and work-related attributes such as education, age, work hours, and gender are also shown to influence employee job satisfaction.Community/Rural/Urban Development, Industrial Organization, Labor and Human Capital,

Social impacts of climate change in Peru : a district level analysis of the effects of recent and future climate change on human development and inequality

This paper uses district level data to estimate the general relationship between climate, income and life expectancy in Peru. The analysis finds that both incomes and life expectancy show hump-shaped relationships, with optimal average annual temperatures around 18-20ºC. These estimated relationships were used to simulate the likely effects of both past (1958-2008) and future (2008-2058) climate change. At the aggregate level, future climate change in Peru is estimated to cause a small reduction in average life expectancy of about 0.2 years. This average, however, hides much larger losses in the already hot areas as well as substantial gains in currently cold areas. Similarly, the average impact on incomes is a modest reduction of 2.3 percent, but with some districts experiencing losses of up to 20 percent and others gains of up to 13 percent. Future climate change is estimated to cause an increase in poverty (all other things equal), but to have no significant effect on the distribution of incomes.Science of Climate Change,Climate Change Mitigation and Green House Gases,Climate Change Economics,Population Policies,Global Environment Facility

Topics in complex multiscale systems: theory and computations of noise-induced transitions and transport in heterogenous media

The present work seeks to address three different problems that have a multiscale nature, we apply different techniques from multiscale analysis to treat these problems. We introduce the field of multiscale analysis and motivate the need for techniques to bridge between scales, presenting the history of some common methods, and an overview of the current state of the field. The remainder of the work deals with the treatment of these problems, one motivated by reaction rate theory, and two from multiphase flow. These superficially have little relation with each other, but the approaches taken share similarities and the results are the same - an average picture of the microscopic description informs the macroscale. In Chapter 2 we address an asymmetric potential with a microscale, showing that the interaction between this microscale and the noise causes a first-order phase transition. This induces a metastable state which we observe and characterise: showing that the stability of this state depends on the strength of the tilt, and that the phase transition is inherently different to the symmetric case. In Chapter 3 we investigate the nucleation and coarsening process of a two-phase flow in a corrugated channel using a Cahn--Hilliard Navier--Stokes model. We show that several flow morphologies can be present depending on the channel geometry and the initial random condition. We rationalise this with a static energy model, predicting the preferential formation of one morphology over another and the existence of a first-order phase-transition from smooth slug flow to discontinuous motion when the channel is strongly corrugated. In Chapter 4 we address a model for interfacial flows in porous geometries, formulating an finite-element model for the equations. Within this framework we solve two equations in the microscale to obtain effective coefficients decoupling the two scales from each other. Finite-difference simulations of the macroscopic flow recover results from literature, supporting robustness of the method.Open Acces

Investigation of the flow in the diffuser section of the NASA Lewis icing research tunnel

The flow in the diffuser section of the Icing Research Wind Tunnel at NASA Lewis Research Center is investigated using both tunnel calibration measurements and numerical simulation techniques. Local pressure and temperature measurements are made to establish velocity and temperature profiles in the diffuser of the tunnel. These profiles are compared with similar measurements made prior to renovating the equipment which generates the tunnel's icing cloud. This comparison indicates the manner in which this change affected the flow. The measured data were also compared with a numerical simulation of the flow to help understand how such changes may favorably alter the tunnel flow

Ready Player Ready Research: A Common Reader Caper

This chapter discusses integrating co-curricular activities to promote and embed common reader material throughout the first year experience

Young People’s Perceptions of Nature and Interactions with National Parks

This thesis examines young people’s perceptions of nature and the outdoors, in order to better understand their interactions and experiences with national parks. Younger generations currently are not engaging with the national parks as much as older generations. This study seeks to understand the reasons behind this change and explore potential solutions to this challenge, as younger generations will be responsible for the conservation and preservation of national parks in the near future. This research was modeled on a previous study based on students at the University of Northern Colorado. Research methodologies included both a survey and focus groups to explore this topic fully. The results indicate that young people desire to spend more time outdoors and visiting National Parks, but cite time, money, transportation, and technology as constraints that prevent them from interacting with nature. Time stands out as the biggest constraint. The focus groups revealed that young people who have a passion will find a way to make time for nature in their busy schedules, as this is a priority for them. As such, encouraging a passion for nature within younger people may help increase their presence in national parks through repeated exposure and positive experiences with the outdoors from a young age

A numerical simulation of the flow in the diffuser of the NASA Lewis icing research tunnel

The flow in the diffuser section of the Icing Research Tunnel at the NASA Lewis Research Center is numerically investigated. To accomplish this, an existing computer code is utilized. The code, known as PARC3D, is based on the Beam-Warming algorithm applied to the strong conservation law form of the complete Navier-Stokes equations. The first portion of the paper consists of a brief description of the diffuser and its current flow characteristics. A brief discussion of the code work follows. Predicted velocity patterns are then compared with the measured values

Is There a Doctor in the Book? A Study of Female Physicians in Literature

Young children often look to characters in books, movies, and television to inspire their future career choices. This research project was designed to examine what female physicians in literature inspired young women to choose to become physicians. It is important to investigate the influences young women may or may not have had so that those inspiring characters if they exist, can be highlighted for future generations. To obtain data, I sent a survey to the Utah State University Pre-Med Club to gauge what literary influences inspired them to become doctors. I also interviewed three female doctors and recorded their influences and thoughts on the representation of female physicians in literature.https://digitalcommons.usu.edu/fsrs2020/1035/thumbnail.jp