Race in Europe

https://digital.kenyon.edu/rarebooks/1015/thumbnail.jp

Transhumanism

In his famous paper, Julian Huxley gives the outline of what he believes future humanity could – and should – look like. By pointing out the numerous limitations and feebleness the human nature is – at the time – prone to, and by confronting them with the possibilities humankind has, Huxley expresses the need to research and put into use all possible measures that would enable man achieve utmost perfection

The Individual in the Animal Kingdom

The groundbreaking first book by a major evolutionary biologist, published in 1912, that anticipated current thinking about organismal complexity. Julian Huxley's The Individual in the Animal Kingdom, published in 1912, is a concise and groundbreaking work that is almost entirely unknown today. In it, Huxley analyzes the evolutionary advances in life's organizational complexity, anticipating many of today's ideas about changes in individuality. Huxley's overarching system of concepts and his coherent logical principles were so far ahead of their time that they remain valid to this day. In part, this is because his explicitly Darwinian approach carefully distinguished between the integrated form and function of hierarchies within organisms and loosely defined, nonorganismal ecological communities. In The Individual in the Animal Kingdom, we meet a youthful Huxley who uses his commanding knowledge of natural history to develop a nonreductionist account of life's complexity that aligns with seminal early insights by Darwin, Wallace, Weismann, and Wheeler. As volume editors Richard Gawne and Jacobus Boomsma point out, this work disappeared into oblivion despite its relevance for contemporary research on organismal complexity and major evolutionary transitions. This MIT Press edition gives Huxley's book a second hearing, offering readers a unique vantage point on the discoveries of evolutionary biology past and present

Transhumanizm

W swojej klasycznej pracy, Julian Huxley formułuje perspektywę możliwej przyszłości gatunku ludzkiego, przyszłości, do której – jak wierzy – winniśmy zdążać. Wskazując na słabości i ograniczenia, jakie napotyka natura  ludzka i odnosząc je do potencjalnych możliwości, jakie przed człowiekiem otwierają osiągnięcia nauk przyrodniczych, Huxley wyraża potrzebę badania i iprowadzania w czyn wszelkich dostępnych środków, które umożliwiłyby gatunkowi ludzkiemu wzięcie steru nad swoją biologiczną ewolucją

Remarks on Muscle Contraction Mechanism II. Isometric Tension Transient and Isotonic Velocity Transient

Mitsui and Ohshima (2008) criticized the power-stroke model for muscle contraction and proposed a new model. In the new model, about 41% of the myosin heads are bound to actin filaments, and each bound head forms a complex MA3 with three actin molecules A1, A2 and A3 forming the crossbridge. The complex translates along the actin filament cooperating with each other. The new model well explained the experimental data on the steady filament sliding. As an extension of the study, the isometric tension transient and isotonic velocity transient are investigated. Statistical ensemble of crossbridges is introduced, and variation of the binding probability of myosin head to A1 is considered. When the binding probability to A1 is zero, the Hill-type force-velocity relation is resulted in. When the binding probability to A1 becomes finite, the deviation from the Hill-type force-velocity relation takes place, as observed by Edman (1988). The characteristics of the isometric tension transient observed by Ford, Huxley and Simmons (1977) and of the isotonic velocity transient observed by Civan and Podolsky (1966) are theoretically reproduced. Ratios of the extensibility are estimated as 0.22 for the crossbridge, 0.26 for the myosin filament and 0.52 for the actin filament, in consistency with the values determined by X-ray diffraction by Wakabayashi et al. (1994)

Interactions between Connected Half-Sarcomeres Produce Emergent Mechanical Behavior in a Mathematical Model of Muscle

Most reductionist theories of muscle attribute a fiber's mechanical properties to the scaled behavior of a single half-sarcomere. Mathematical models of this type can explain many of the known mechanical properties of muscle but have to incorporate a passive mechanical component that becomes ∼300% stiffer in activating conditions to reproduce the force response elicited by stretching a fast mammalian muscle fiber. The available experimental data suggests that titin filaments, which are the mostly likely source of the passive component, become at most ∼30% stiffer in saturating Ca2+ solutions. The work described in this manuscript used computer modeling to test an alternative systems theory that attributes the stretch response of a mammalian fiber to the composite behavior of a collection of half-sarcomeres. The principal finding was that the stretch response of a chemically permeabilized rabbit psoas fiber could be reproduced with a framework consisting of 300 half-sarcomeres arranged in 6 parallel myofibrils without requiring titin filaments to stiffen in activating solutions. Ablation of inter-myofibrillar links in the computer simulations lowered isometric force values and lowered energy absorption during a stretch. This computed behavior mimics effects previously observed in experiments using muscles from desmin-deficient mice in which the connections between Z-disks in adjacent myofibrils are presumably compromised. The current simulations suggest that muscle fibers exhibit emergent properties that reflect interactions between half-sarcomeres and are not properties of a single half-sarcomere in isolation. It is therefore likely that full quantitative understanding of a fiber's mechanical properties requires detailed analysis of a complete fiber system and cannot be achieved by focusing solely on the properties of a single half-sarcomere