Causes that Make a Difference

Biologists studying complex causal systems typically identify some factors as causes and treat other factors as background conditions. For example, when geneticists explain biological phenomena, they often foreground genes and relegate the cellular milieu to the background. But factors in the milieu are as causally necessary as genes for the production of phenotypic traits, even traits at the molecular level such as amino acid sequences. Gene-centered biology has been criticized on the grounds that because there is parity among causes, the “privileging” of genes reflects a reductionist bias, not an ontological difference. The idea that there is an ontological parity among causes is related to a philosophical puzzle identified by John Stuart Mill: what, other than our interests or biases, could possibly justify identifying some causes as the actual or operative ones, and other causes as mere background? The aim of this paper is to solve this conceptual puzzle and to explain why there is not an ontological parity among genes and the other factors. It turns out that solving this puzzle helps answer a seemingly unrelated philosophical question: what kind of causal generality matters in biology

Muslim Head Coverings

I researched female head coverings in the Muslim culture, to see how the veils affected society and society\u27s response to the covering

Improved high-temperature-strength nickel-base superalloy

Nickel-base superalloy has a strength of 20,000 psi at 2,200 degrees F, approximately double the strength of the strongest available cast nickel-base alloys. It is not subject to the formation of embrittling phases upon long time exposure at intermediate temperatures

Stabilizing periodic orbits above the elliptic plane in the solar sail 3-body problem

We consider periodic orbits high above the ecliptic plane in the Elliptic Restricted Three-Body Problem where the third massless body is a solar sail. Periodic orbits above the ecliptic are of practical interest as they are ideally positioned for the year-round constant imaging of, and communication with, the poles. Initially we identify an unstable periodic orbit by using a numerical continuation from a known periodic orbit above the ecliptic in the circular case with the eccentricity as the varying parameter. This orbit is then used to construct a reference trajectory for the sail to track. In addition we illustrate an alternative method for constructing a periodic reference trajectory based on a time-delayed feedback mechanism. The reference trajectories are then tracked using a linear feedback regulator (LQR) where the control actuation is delivered by varying the solar sails orientation. Using this method it is shown that a 'near term' solar sail is capable of performing stable periodic motions high above the ecliptic

High strength nickel base alloy, WAZ-16, for applications up to 2200 F

Alloy product is high strength, high temperature nickel base material with higher incipient melting temperature than all known nickel base alloys. It is microstructurally stable and has high impact resistance both before and after prolonged thermal exposure. It contains relatively few alloying constitutents and low content of expensive and rare metals

High strength nickel-base alloy with improved oxidation resistance up to 2200 degrees F

Modifying the chemistry of the NASA TAZ-8 alloy and utilizing vacuum melting techniques provides a high strength, workable nickel base superalloy with improved oxidation resistance for use up to 2200 degrees F

New periodic orbits in the solar sail restricted three body problem

In this paper we consider periodic orbits of a solar sail in the Earth-Sun restricted three-body problem. In particular, we consider orbits which are high above the ecliptic plane, in contrast to the classical Halo orbits about the collinear equilibria. We begin with the Circular Restricted Three-Body Problem (CRTBP) where periodic orbits about equilibria are naturally present at linear order. Using the method of Lindstedt-Poincaré, we construct nth order approximations to periodic solutions of the nonlinear equations of motion. In the second part of the paper we generalize to the Elliptic Restricted Three Body Problem (ERTBP). A numerical continuation, with the eccentricity, e, as the varying parameter, is used to find periodic orbits above the ecliptic, starting from a known orbit at e = 0 and continuing to the required eccentricity of e = 0:0167. The stability of these periodic orbits is investigated

Nickel-base alloy containing Mo-W-Al-Cr- Ta-Zr-C-Nb-B Patent

Nickel base alloy with resistance to oxidation at high temperatures and superior stress-rupture propertie