The Unluckiest Quality Individual Stock Investor versus Quality Index Investing

This paper will compare the results of two individuals investing $125,000 each in the stock market over a 15-year period. One invests the entire$125,000 as an initial lump sum into a market basket of stocks. The other initially invests only a portion of the $125,000 into a collection of randomly selected quality dividend paying stocks while investing the remaining portion into the same stocks on a quarterly basis over 15 years. This second investor unluckily always invests at the high points of the market. Both investors reinvest the dividends. The comparison of the two investment strategies is astonishing

The Role of Vaccination, Antiorthopoxvirus Drug, and Social Cooperativity in a Mathematical Model of Smallpox Control

Considerable effort has gone into making mathematical and computer models of smallpox spread and control measures, typically consisting of vaccination and quarantine. The orally available antiorthopoxvirus drug tecovirimat has recently completed Phase 2 clinical trials and shows promise as a smallpox control agent. We constructed 2 computer simulations to explore the use of tecovirimat in combination with vaccination and social cooperativity to control an outbreak. Two scenarios were considered: (1) a homogenously mixed, deterministic simulation of a single metropolitan area; and (2) a stochastic network of the 50 largest US metropolitan areas connected by commercial air traffic. Metropolitan-level mass vaccination coupled with drug treatment for all individuals who develop a fever considerably outperforms treating only those who develop smallpox's distinctive rash. Incorporating mass chemoprophylaxis represents another large improvement. More aggressive responses are more robust to low cooperation of the population with public health efforts and to faster disease spread. However, even with the most aggressive public health intervention, an attack that initially infects hundreds or thousands of individuals will need to be fought in multiple cities across the country.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140318/1/bsp.2012.0037.pd

Designed for Disease: The Link Between Local Food Environments and Obesity and Diabetes

Examines the link between a community's retail food environment -- the ratio of fast-food outlets and convenience stores to grocery stores and produce vendors, with income level as a factor -- and the prevalence of adult obesity and diabetes

Stochastic Modeling and Control of Biological Systems: The Lactose Regulation System of Escherichia Coli

In this paper, we present a comprehensive framework for stochastic modeling, model abstraction, and controller design for a biological system. The first half of the paper concerns modeling and model abstraction of the system. Most models in systems biology are deterministic models with ordinary differential equations in the concentration variables. We present a stochastic hybrid model of the lactose regulation system of E. coli bacteria that capture important phenomena which cannot be described by continuous deterministic models.We then show that the resulting stochastic hybrid model can be abstracted into a much simpler model, a two-state continuous-time Markov chain. The second half of the paper discusses controller design for a specific architecture. The architecture consists of measurement of a global quantity in a colony of bacteria as an output feedback and manipulation of global environmental variables as control actuation. We show that controller design can be performed on the abstracted (Markov chain) model and implementation on the real model yields the desired result

Modeling and Analyzing Biomolecular Networks

The authors argue for the need to model and analyze biological networks at molecular and cellular levels. They propose a computational toolbox for biologists. Central to their approach is the paradigm of hybrid models in which discrete events are combined with continuous differential equations to capture switching behavior

Stability and reachability analysis of a hybrid model of luminescence in the marine bacterium \u3ci\u3eVibrio fischeri\u3c/i\u3e

This paper addresses the mathematical modeling and analysis of the quorum sensing system found in unicellular bacteria that exhibit bioluminescence. The luminescence is governed by the expression of genes in the cell, which in turn is controlled by the density of cells in a population. The paper illustrates the application of standard tools in control theory and some recent tools in hybrid systems to the quorum sensing system, and demonstrates that bioluminescence can be modeled and understood as the output of a switched dynamical system

A black hole solution to the cosmological monopole problem

We propose a solution to the cosmological monopole problem: Primordial black holes, produced in the early universe, can accrete magnetic monopoles before the relics dominate the energy density of the universe. These small black holes quickly evaporate and thereby convert most of the monopole energy density into radiation. We estimate the range of parameters for which this solution is possible: under very conservative assumptions we find that the black hole mass must be less than 10^9 gm.Comment: accepted for publication in Phys. Lett.

Reading with peripheral vision: A comparison of reading dynamic scrolling and static text with a simulated central scotoma

AbstractHorizontally scrolling text is, in theory, ideally suited to enhance viewing strategies recommended to improve reading performance under conditions of central vision loss such as macular disease, although it is largely unproven in this regard. This study investigated if the use of scrolling text produced an observable improvement in reading performed under conditions of eccentric viewing in an artificial scotoma paradigm. Participants (n=17) read scrolling and static text with a central artificial scotoma controlled by an eye-tracker. There was an improvement in measures of reading accuracy, and adherence to eccentric viewing strategies with scrolling, compared to static, text. These findings illustrate the potential benefits of scrolling text as a potential reading aid for those with central vision loss

Physical Pictures of Transport in Heterogeneous Media: Advection-Dispersion, Random Walk and Fractional Derivative Formulations

The basic conceptual picture and theoretical basis for development of transport equations in porous media are examined. The general form of the governing equations is derived for conservative chemical transport in heterogeneous geological formations, for single realizations and for ensemble averages of the domain. The application of these transport equations is focused on accounting for the appearance of non-Fickian (anomalous) transport behavior. The general ensemble-averaged transport equation is shown to be equivalent to a continuous time random walk (CTRW) and reduces to the conventional forms of the advection-dispersion equation (ADE) under highly restrictive conditions. Fractional derivative formulations of the transport equations, both temporal and spatial, emerge as special cases of the CTRW. In particular, the use in this context of L{\'e}vy flights is critically examined. In order to determine chemical transport in field-scale situations, the CTRW approach is generalized to non-stationary systems. We outline a practical numerical scheme, similar to those used with extended geological models, to account for the often important effects of unresolved heterogeneities.Comment: 14 pages, REVTeX4, accepted to Wat. Res. Res; reference adde

After the RCT: who comes to a family-based intervention for childhood overweight or obesity when it is implemented at scale in the community?

Background: When implemented at scale, the impact on health and health inequalities of public health interventions depends on who receives them in addition to intervention effectiveness. Methods: The MEND 7–13 (Mind, Exercise, Nutrition…Do it!) programme is a family-based weight management intervention for childhood overweight and obesity implemented at scale in the community. We compare the characteristics of children referred to the MEND programme (N=18 289 referred to 1940 programmes) with those of the population eligible for the intervention, and assess what predicts completion of the intervention. Results: Compared to the MEND-eligible population, proportionally more children who started MEND were: obese rather than overweight excluding obese; girls; Asian; from families with a lone parent; living in less favourable socioeconomic circumstances; and living in urban rather than rural or suburban areas. Having started the programme, children were relatively less likely to complete it if they: reported ‘abnormal’ compared to ‘normal’ levels of psychological distress; were boys; were from lone parent families; lived in less favourable socioeconomic circumstances; and had participated in a relatively large MEND programme group; or where managers had run more programmes. Conclusions: The provision and/or uptake of MEND did not appear to compromise and, if anything, promoted participation of those from disadvantaged circumstances and ethnic minority groups. However, this tendency was diminished because programme completion was less likely for those living in less favourable socioeconomic circumstances. Further research should explore how completion rates of this intervention could be improved for particular groups