The three different phases in the dynamics of chemical reaction networks and their relationship to cancer

We investigate the catalytic reactions model used in cell modeling. The reaction kinetic is defined through the energies of different species of molecules following random independent distribution. The related statistical physics model has three phases and these three phases emerged in the dynamics: fast dynamics phase, slow dynamic phase and ultra-slow dynamic phase. The phenomenon we found is a rather general, does not depend on the details of the model. We assume as a hypothesis that the transition between these phases (glassiness degrees) is related to cancer. The imbalance in the rate of processes between key aspects of the cell (gene regulation, protein-protein interaction, metabolical networks) creates a change in the fine tuning between these key aspects, affects the logics of the cell and initiates cancer. It is probable that cancer is a change of phase resulting from increased and deregulated metabolic reactions.Comment: 5 pages, 2 figures, EPL, in pres

Modern Cavemen? Stereotypes and Reality of the Ancestral Health Movement

Both academic and popular interest in the ancestral health movement, or “paleo” lifestyle, has grown rapidly in recent years. More people than ever are joining the movement, and more books and articles are being published on the topic. Media coverage and certain societal preconceptions of the movement have also increased. More often than not, followers of a paleo lifestyle are thought to be “modern cavemen”: athletic, single, meat-eating, young, white, and male. To test whether or not these stereotypes are true, the authors of the present study created the first large, academic survey (N = 3,967) of the ancestral health community. Specifically, the online survey sought to accomplish two main goals: (1) describe the current composition and demographic makeup of the ancestral health movement and (2) identify common practices, the major obstacles, and the most important motivating factors for adopting a paleo lifestyle. Despite the common stereotypes, survey evidence suggests that the majority of participants are: white, female, middle aged (mean 38 years old), in a committed relationship, highly educated, relatively affluent, and motivated by weight loss and health concerns. Thus, while some of the common preconceptions may hold up, many others probably do not

Differential alphav integrin-mediated Ras-ERK signaling during two pathways of angiogenesis.

Antagonists of alphavbeta3 and alphavbeta5 disrupt angiogenesis in response to bFGF and VEGF, respectively. Here, we show that these alphav integrins differentially contribute to sustained Ras-extracellular signal-related kinase (Ras-ERK) signaling in blood vessels, a requirement for endothelial cell survival and angiogenesis. Inhibition of FAK or alphavbeta5 disrupted VEGF-mediated Ras and c-Raf activity on the chick chorioallantoic membrane, whereas blockade of FAK or integrin alphavbeta3 had no effect on bFGF-mediated Ras activity, but did suppress c-Raf activation. Furthermore, retroviral delivery of active Ras or c-Raf promoted ERK activity and angiogenesis, which anti-alphavbeta5 blocked upstream of Ras, whereas anti-alphavbeta3 blocked downstream of Ras, but upstream of c-Raf. The activation of c-Raf by bFGF/alphavbeta3 not only depended on FAK, but also required p21-activated kinase-dependent phosphorylation of serine 338 on c-Raf, whereas VEGF-mediated c-Raf phosphorylation/activation depended on Src, but not Pak. Thus, integrins alphavbeta3 and alphavbeta5 differentially regulate the Ras-ERK pathway, accounting for distinct vascular responses during two pathways of angiogenesis

Standards of Proof in Civil Litigation: An Experiment from Patent Law

Standards of proof are widely assumed to matter in litigation. They operate to allocate the risk of error between litigants, as well as to indicate the relative importance attached to the ultimate decision. But despite their perceived importance, there have been relatively few empirical studies testing jurors’ comprehension and application of standards of proof, particularly in civil litigation. Patent law recently presented an opportunity to assess the potential impact of varying the standard of proof in civil cases. In Microsoft Corp. v. i4i Limited Partnership, the Supreme Court held that a patent’s presumption of validity can only be overcome by clear and convincing evidence. However, it also explained that the jury should be instructed that it may be easier to satisfy this standard when the party challenging the patent’s validity offered evidence that was not previously been considered by the U.S. Patent & Trademark Office. In this project, we conducted an experimental study to test the impact of standards of proof in patent invalidity challenges. We found that delivering the jury instruction directed by the i4i decision resulted in mock jurors finding a patent invalid at rates statistically indistinguishable from the preponderance of the evidence standard explicitly rejected by the Court in that case. This surprising result suggests that Microsoft may have actually achieved its desired outcome in i4i by making it easier for juries to invalidate questionable patents, even though it lost the case

Executive Dismissal or Retention? A Study of Performance, Power, and Survival for College Basketball Coaches

This study applies upper echelons theory associated with executive dismissal and power to examine the relationships of performance and four types of executive power—structural, prestige, expert, and governance concentration—with dismissal. Using the context of National Collegiate Athletic Association college basketball, in which coaches are completely responsible for strategies and human capital acquisition and retention, a curvilinear relationship between performance and dismissal is found. Significant relationships for prestige and expert power with dismissal are also found, but the “honeymoon period” is longer than prior studies of executive and coach dismissal have shown. Surprisingly, concentrated governance is found to be negatively associated with the likelihood of dismissal

Wildlife Scientists and Wilderness Managers Finding Common Ground with Noninvasive and Nonintrusive Sampling of Wildlife

Iconic wildlife species such as grizzly bears, wolves, lynx, and wolverines are often associated with wilderness. Wilderness may provide some of the last, and best, remaining places for such species because wilderness can offer long-term legislated protection, relatively large areas, and remoteness (Mattson 1997). Indeed, the word wilderness in its original form literally means “place of wild beasts” (Nash 1982). Despite this natural fit between wilderness and wildlife, simply drawing a boundary around an area such as wilderness does not assure the protection and persistence of wildlife either inside the area or across the broader landscape (Landres et al. 1998). Only by understanding where such species occur and how their populations are faring can we know if wilderness is aiding in the role of sustaining wildlif

Multi-scale continuum mechanics: from global bifurcations to noise induced high-dimensional chaos

Many mechanical systems consist of continuum mechanical structures, having either linear or nonlinear elasticity or geometry, coupled to nonlinear oscillators. In this paper, we consider the class of linear continua coupled to mechanical pendula. In such mechanical systems, there often exist several natural time scales determined by the physics of the problem. Using a time scale splitting, we analyze a prototypical structural–mechanical system consisting of a planar nonlinear pendulum coupled to a flexible rod made of linear viscoelastic material. In this system both low-dimensional and high-dimensional chaos is observed. The low-dimensional chaos appears in the limit of small coupling between the continua and oscillator, where the natural frequency of the primary mode of the rod is much greater than the natural frequency of the pendulum. In this case, the motion resides on a slow manifold. As the coupling is increased, global motion moves off of the slow manifold and high-dimensional chaos is observed. We present a numerical bifurcation analysis of the resulting system illustrating the mechanism for the onset of high-dimensional chaos. Constrained invariant sets are computed to reveal a process from low-dimensional to high-dimensional transitions. Applications will be to both deterministic and stochastic bifurcations. Practical implications of the bifurcation from low-dimensional to high-dimensional chaos for detection of damage as well as global effects of noise will also be discussed

On Negative Outcome Control of Unobserved Confounding as a Generalization of Difference-in-Differences

The difference-in-differences (DID) approach is a well known strategy for estimating the effect of an exposure in the presence of unobserved confounding. The approach is most commonly used when pre-and post-exposure outcome measurements are available, and one can assume that the association of the unobserved confounder with the outcome is equal in the two exposure groups, and constant over time. Then, one recovers the treatment effect by regressing the change in outcome over time on the exposure. In this paper, we interpret the difference-in-differences as a negative outcome control (NOC) approach. We show that the pre-exposure outcome is a negative control outcome, as it cannot be influenced by the subsequent exposure, and it is affected by both observed and unobserved confounders of the exposure-outcome association of interest. The relation between DID and NOC provides simple conditions under which negative control outcomes can be used to detect and correct for confounding bias. However, for general negative control outcomes, the DID-like assumption may be overly restrictive and rarely credible, because it requires that both the outcome of interest and the control outcome are measured on the same scale. Thus, we present a scale-invariant generalization of the DID that may be used in broader NOC contexts. The proposed approach is demonstrated in simulations and on a Normative Aging Study data set, in which Body Mass Index is used for NOC of the relationship between air pollution and inflammatory outcomes