Information-adaptive clinical trials: a selective recruitment design

We propose a novel adaptive design for clinical trials with time-to-event outcomes and covariates (which may consist of or include biomarkers). Our method is based on the expected entropy of the posterior distribution of a proportional hazards model. The expected entropy is evaluated as a function of a patient's covariates, and the information gained due to a patient is defined as the decrease in the corresponding entropy. Candidate patients are only recruited onto the trial if they are likely to provide sufficient information. Patients with covariates that are deemed uninformative are filtered out. A special case is where all patients are recruited, and we determine the optimal treatment arm allocation. This adaptive design has the advantage of potentially elucidating the relationship between covariates, treatments, and survival probabilities using fewer patients, albeit at the cost of rejecting some candidates. We assess the performance of our adaptive design using data from the German Breast Cancer Study group and numerical simulations of a biomarker validation trial

Fish for the city: meta-analysis of archaeological cod remains and the growth of London’s northern trade

The growth of medieval cities in Northern Europe placed new demands on food supply, and led to the import of fish from increasingly distant fishing grounds. Quantitative analysis of cod remains from London provides revealing insight into the changing patterns of supply that can be related to known historical events and circumstances. In particular it identifies a marked increase in imported cod from the thirteenth century AD. That trend continued into the fifteenth and sixteenth centuries, after a short downturn, perhaps attributable to the impact of the Black Death, in the mid fourteenth century. The detailed pattern of fluctuating abundance illustrates the potential of archaeological information that is now available from the high-quality urban excavations conducted in London and similar centres during recent decades

PREVENTION AND TREATMENT IN FOOD SAFETY: AN ANALYSIS OF CONCEPTUAL ISSUES

Foodborne illness, damage functions, optimal regulation, Food Consumption/Nutrition/Food Safety,

On Einstein Algebras and Relativistic Spacetimes

In this paper, we examine the relationship between general relativity and the theory of Einstein algebras. We show that according to a formal criterion for theoretical equivalence recently proposed by Halvorson (2012, 2015) and Weatherall (2015), the two are equivalent theories.Comment: 20 page

Modeling Fluid Phenomena in the Context of the Constrained Vapor Bubble System

This thesis focuses on the fluid phenomena observed within what is known as the constrained vapor bubble system. The constrained vapor bubble system is a closed system consisting of a quartz cuvette partially filled with liquid and used as a coolant device. Heat is applied to the heater end which causes the liquid to evaporate and condense on the cooled end of the cuvette. Liquid travels back to the heated end via capillary flow in the corners. A pure vapor bubble is formed in the center of the cuvette giving rise to the name of the experiment. The constrained vapor bubble system is important due to its potential use for cooling devices in microgravity since it does not require a metal wick or gravity used by most micro heat pipes. Experiments done onboard the International Space Station showed fluid phenomena inconsistent with mathematical models and experiments performed in earth\u27s environment. Most notably a flooded heater end and droplets forming on the four walls of the cuvette. 1-dimensional and 2-dimensional heat transfer models are presented. Novel mathematical models of heat transfer and fluid flow in the constrained vapor bubble system are developed in the thesis. Fitting the experimental data from \cite{chatterjee2013} to the 1D heat transfer model in the region near the hot end leads to an estimate of the internal heat transfer coefficient of 400 W/(m$^2$ K) there. However, the heat transfer coefficient is found to increase in the condensation zone near the middle of the cuvette, an observation explained by increased liquid-vapor interface area. Finally, near the cold end the heat transfer is dominated by axial conduction in the liquid phase that fills most of the cross-section and the heat transfer coefficient drops to zero. In the 2D cross-sectional model for temperature the evaporative flux is calculated by taking into account heat transfer in the liquid phase in the corners of the cuvette and introducing a localized cooling parameter into the boundary conditions at the cuvette walls. Heat flux at the liquid-vapor interface is determined and used to estimate the evaporative loss and thus the axial velocity of the flow, with typical average axial flow velocity found to be of the order of 1 mm/s. An analytical estimate of flow velocity is obtained and is shown to be consistent with the numerical results. Effects of 3D heat conduction in the cuvette and the Marangoni stresses are also studied. Further investigation is needed to fully understand the mechanisms of the flow slow-down in the evaporation region. A mathematical model is developed of an evaporating droplet observed in the constrained vapor bubble experimental set-up. The motion of receding contact line is described using two-component disjoining pressure coupled with the effects of phase change and capillarity. The results include dynamics of interface shapes during droplet evaporation, including the radius of curvature at the top of the droplet expressed in dimensional form. The evaporative flux is found to increase toward the contact line, but not as sharply as in the case of evaporating meniscus due to the addition of localized cooling of the substrate. Detailed studies of the the effect of evaporative cooling parameter $K_s$ on the solutions are conducted. Increase in $K_s$ leads to lower local heat flux near the contact line and thus slower evaporation. Radius of curvature at the top of the droplet is found to decrease in a linear fashion with the slope consistent with experimentally measured values. A second term in the disjoining pressure gives excellent control over contact angle for matching with experiments or observing different regimes

Immigrants and Immigration - Below the Surface of the 2008 Election

"National coverage of the 2008 presidential race offers enough drama to keep analysts busy. With the Democrats favored to win the national election as a result of the disastrous foreign and domestic policies of the Bush administration, many Americans have been looking forward to one or another historic first. The Democrats would nominate either a woman or an African American for president. Of course, third parties, including the Communist Party of the USA, have nominated women, African Americans, and other candidates of color in the past, but it seemed impossible just a year or two ago that a major party would make such a move. It is now clear that Barack Obama will receive the Democratic nomination. He faces a formidable opponent with all the resources American conservatives and reactionaries can muster to defeat him in the general election, but the fact is that a fairly liberal candidate who identifies and is identified as African American stands a good chance of winning the election and taking the United States in a different direction from the policies of the past decade. This is indeed a historic moment, and it is no wonder that this national story has grabbed all the headlines."(...

Bartram Healthy Lifestyles Initiative

https://digitalcommons.pcom.edu/bridging_gaps2014/1020/thumbnail.jp

Long- and short-range correlations in the ab-initio no-core shell model

In the framework of the ab-initio no-core shell model (NCSM), we describe the longitudinal-longitudinal distribution function, part of the inclusive (e,e') longitudinal response. In the two-body cluster approximation, we compute the effective operators consistent with the unitary transformation used to obtain the effective Hamiltonian. When short-range correlations are probed, the results display independence from the model space size and length scale. Long-range correlations are more difficult to model in the NCSM and they can be described only by increasing the model space or increasing the cluster size. In order to illustrate the model space independence for short-range observables, we present results for a large set of model spaces for 4He, and in 0-4hw model spaces for 12C.Comment: 4 pages, 4 figure

The oxidation of Ni-rich Ni-Al intermetallics

The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni3Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al2O3 scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field