Cloned Meat, Voluntary Food Labeling, and Organic Oreos

[Excerpt] “In December 2006, the Food and Drug Administration (FDA) announced that it had reviewed all the available evidence and was poised to approve meat and milk from cloned animals and their progeny. I remember telling one of my colleagues, a patent law professor, who should be as comfortable with technology as anyone, about this development, and his response was, “Yuck. I’m not eating it!” To which of course I replied, “Humph. You won’t know the difference.” Meat or milk from a clone or its descendant is virtually identical to meat or milk from a non-clone, said the FDA, as it also announced that it would almost certainly not require food from clones to be labeled. Consumers often want information about where their food came from or about the processes employed in producing it. The food identity approach to labeling cannot take process into account unless the process affects the identity of the food. When the process does not change the food in any material way, process information on a label might suggest a difference that does not exist. The instinctive “yuck” to the thought of cloned meat highlights the tension between consumer preferences, the government’s science-based, food identity approach, and producers’ efforts to differentiate their products. Part I of this article identifies three functions that labels perform, outlines the types of information usually required, and introduces the rule that voluntary label information cannot be misleading. Part II focuses on process information and its implications. I argue that there is no truly voluntary labeling when consumers care about a feature; if some products are labeled, then unlabeled products bear a de facto label by implication. Partly because of the de facto mandatory labeling principle, process labeling has the potential to mislead consumers. In Part III, I examine some relevant characteristics of consumers. I argue that not all consumers can be misled by label information. Consumers who have no preferences or who are very knowledgeable about the labeled feature are not misled by process labeling. Finally, using labeling of genetically modified (GM) ingredients as an example, I suggest that mandatory labeling of some process information could enhance consumer sovereignty and welfare.

Mathematical biomedicine and modeling avascular tumor growth

In this chapter we review existing continuum models of avascular tumor growth, explaining howthey are inter related and the biophysical insight that they provide. The models range in complexity and include one-dimensional studies of radiallysymmetric growth, and two-dimensional models of tumor invasion in which the tumor is assumed to comprise a single population of cells. We also present more detailed, multiphase models that allow for tumor heterogeneity. The chapter concludes with a summary of the different continuum approaches and a discussion of the theoretical challenges that lie ahead

Carpet plot data format

Analysis and interpretation of data is the crucial phase of the decision making process. The interplay between variables must be considered as to their relative significance upon the final result, and sometimes time-sensitive decisions must be made when actual events deviate from predicted information, such as Apollo 13. As the number of variables increases past say four, the traditional method of cross-plotting tends to break down, and digital/analog results cannot present a sharply defined method of analysis. A graphical system, the carpet plot, is presented in which an unlimited number of complicated relationships of variables can be evaluated

Multiphase modelling of vascular tumour growth in two spatial dimensions

In this paper we present a continuum mathematical model of vascular tumour growth which is based on a multiphase framework in which the tissue is decomposed into four distinct phases and the principles of conservation of mass and momentum are applied to the normal/healthy cells, tumour cells, blood vessels and extracellular material. The inclusion of a diffusible nutrient, supplied by the blood vessels, allows the vasculature to have a nonlocal influence on the other phases. Two-dimensional computational simulations are carried out on unstructured, triangular meshes to allow a natural treatment of irregular geometries, and the tumour boundary is captured as a diffuse interface on this mesh, thereby obviating the need to explicitly track the (potentially highly irregular and ill-defined) tumour boundary. A hybrid finite volume/finite element algorithm is used to discretise the continuum model: the application of a conservative, upwind, finite volume scheme to the hyperbolic mass balance equations and a finite element scheme with a stable element pair to the generalised Stokes equations derived from momentum balance, leads to a robust algorithm which does not use any form of artificial stabilisation. The use of a matrix-free Newton iteration with a finite element scheme for the nutrient reaction-diffusion equations allows full nonlinearity in the source terms of the mathematical model. Numerical simulations reveal that this four-phase model reproduces the characteristic pattern of tumour growth in which a necrotic core forms behind an expanding rim of well-vascularised proliferating tumour cells. The simulations consistently predict linear tumour growth rates. The dependence of both the speed with which the tumour grows and the irregularity of the invading tumour front on the model parameters are investigated

Dynamic confidence during simulated clinical tasks

Objective: Doctors' confidence in their actions is important for clinical performance. While static confidence has been widely studied, no study has examined how confidence changes dynamically during clinical tasks. Method: The confidence of novice (n = 10) and experienced (n = 10) trainee anaesthetists was measured during two simulated anaesthetic crises, bradycardia (easy task) and failure to ventilate (difficult task). Results: As expected, confidence was high in the novice and experienced groups in the easy task. What was surprising, however, was that confidence during the difficult task decreased for both groups, despite appropriate performance. Conclusions: Given that confidence affects performance, it is alarming that doctors who may be acting unsupervised should lose dynamic confidence so quickly. Training is needed to ensure that confidence does not decrease inappropriately during a correctly performed procedure. Whether time on task interacts with incorrect performance to produce further deficits in confidence should now be investigated

Turbulence damping as a measure of the flow dimensionality

The dimensionality of turbulence in fluid layers determines their properties. We study electromagnetically driven flows in finite depth fluid layers and show that eddy viscosity, which appears as a result of three-dimensional motions, leads to increased bottom damping. The anomaly coefficient, which characterizes the deviation of damping from the one derived using a quasi-two-dimensional model, can be used as a measure of the flow dimensionality. Experiments in turbulent layers show that when the anomaly coefficient becomes high, the turbulent inverse energy cascade is suppressed. In the opposite limit turbulence can self-organize into a coherent flow.Comment: 4 pages, 4 figure

Calculus from the past: multiple delay systems arising in cancer cell modelling

Non-local calculus is often overlooked in the mathematics curriculum. In this paper we present an interesting new class of non-local problems that arise from modelling the growth and division of cells, especially cancer cells, as they progress through the cell cycle. The cellular biomass is assumed to be unstructured in size or position, and its evolution governed by a time-dependent system of ordinary differential equations with multiple time delays. The system is linear and taken to be autonomous. As a result, it is possible to reduce its solution to that of a nonlinear matrix eigenvalue problem. This method is illustrated by considering case studies, including the model of the cell cycle developed in Simms K, Bean N, & Koeber A. [10]. The paper concludes by explaining how asymptotic expressions for the distribution of cells across the compartments can be determined and used to assess the impact of different chemotherapeutic agents