The Chromosome Cycle

The Chromosome Cycle
Author: Bernard John
Publisher: Springer Science & Business Media
Total Pages: 132
Release: 2012-12-06
Genre: Science
ISBN: 3709155908

neoessity for making it. Yet, clearly, the problem of development is largely one of filling "the vacuum between determinant and character" (DARLINGTON 1951). Nowadays the chromosome theory can be presented in much greater detail and with utter confidence, but its two main features remain the same. However, while the role of the chromosomes in heredity and development has been appreciated for a long time, the manner in which they perform their genetic and epigenetic functions has become amenable to critical investigation only in recent years. There is, therefore, still an unmistakable tendency to think of chromosomes in terms of the discrete threads of cell division and, in keeping with this conception, the chromosome cycle is gen erally considered in relation to the microscopically visible changes in morphology which occur during the mechanically active phases of mitosis and meiosis. Chromosome phenotype, however, changes not only during division but throughout the cell cycle. The changes which occur during interphase are, of course, scarcely revealed in morphological modifications of the restless "resting" nucleus. Consequently they are less obvious and correspondingly less amenable to investigation. This accounts for the concentration on the countable karyotype, with its visible properties of pairing and pycnosity, and the measurable movements of separation and segregation.

The Chromosome Complement

The Chromosome Complement
Author: Bernard John
Publisher: Springer
Total Pages: 210
Release: 1968
Genre: Science
ISBN: 9783211808818

material can serve both autocatalytic and heterocatalytic functions. Thus not only is it unique in itB capacity for self-replication but its base sequence determines the specificity of proteins. And enzyme proteins are immediately responsible for the peripheral metabolism which enables the organism to impose its own kind of order on the raw materials it absorbs. The course of development is determined not only by the nature of the genetic material but by its over-all amount and the relative frequency of the different functional units. Differential rates of epigenetic activity matter also. In theory, therefore, differential development within or even between individuals could be determined by the differential replication of the various genetic elements or by their differential activity. And further variation could arise by the differential transmission of these elements between cells. Indeed it would appear that all these possibilities are exploited by living systems. If like is to beget like, however, any genetic change which occurs during development must be undone, or else germinal units preserved from change must be set aside. As far as is known, genetic changes, even those involving only quantity or relative amounts, are reversible to only a very limited extent so that a change once done cannot be undone. Consequently genetic changes during the development of presumptive germ-lines are either non existant or minor and confined to a small class of un aggregated deter minants.

Pearls from a Lost City

Pearls from a Lost City
Author: Roman Duda
Publisher: American Mathematical Society
Total Pages: 247
Release: 2014-08-07
Genre: Biography & Autobiography
ISBN: 1470410761

The fame of the Polish school at Lvov rests with the diverse and fundamental contributions of Polish mathematicians working there during the interwar years. In particular, despite material hardship and without a notable mathematical tradition, the school made major contributions to what is now called functional analysis. The results and names of Banach, Kac, Kuratowski, Mazur, Nikodym, Orlicz, Schauder, Sierpiński, Steinhaus, and Ulam, among others, now appear in all the standard textbooks. The vibrant joie de vivre and singular ambience of Lvov's once scintillating social scene are evocatively recaptured in personal recollections. The heyday of the famous Scottish Café--unquestionably the most mathematically productive cafeteria of all time--and its precious Scottish Book of highly influential problems are described in detail, revealing the special synergy of scholarship and camaraderie that permanently elevated Polish mathematics from utter obscurity to global prominence. This chronicle of the Lvov school--its legacy and the tumultuous historical events which defined its lifespan--will appeal equally to mathematicians, historians, or general readers seeking a cultural and institutional overview of key aspects of twentieth-century Polish mathematics not described anywhere else in the extant English-language literature.

The Doflein Method

The Doflein Method
Author: Elma Doflein
Publisher: Schott Music
Total Pages: 65
Release: 2020-12-23
Genre: Music
ISBN: 379578770X

The Doflein Method. The Violinist's Progress. Volume I: The higher positions (4th to 10th positions) A course of violin instruction combined with musical theory and practice in duet-playing.

The Physicist and the Philosopher

The Physicist and the Philosopher
Author: Jimena Canales
Publisher: Princeton University Press
Total Pages: 488
Release: 2015-06-09
Genre: Science
ISBN: 1400865778

The explosive debate that transformed our views about time and scientific truth On April 6, 1922, in Paris, Albert Einstein and Henri Bergson publicly debated the nature of time. Einstein considered Bergson's theory of time to be a soft, psychological notion, irreconcilable with the quantitative realities of physics. Bergson, who gained fame as a philosopher by arguing that time should not be understood exclusively through the lens of science, criticized Einstein's theory of time for being a metaphysics grafted on to science, one that ignored the intuitive aspects of time. The Physicist and the Philosopher tells the remarkable story of how this explosive debate transformed our understanding of time and drove a rift between science and the humanities that persists today. Jimena Canales introduces readers to the revolutionary ideas of Einstein and Bergson, describes how they dramatically collided in Paris, and traces how this clash of worldviews reverberated across the twentieth century. She shows how it provoked responses from figures such as Bertrand Russell and Martin Heidegger, and carried repercussions for American pragmatism, logical positivism, phenomenology, and quantum mechanics. Canales explains how the new technologies of the period—such as wristwatches, radio, and film—helped to shape people’s conceptions of time and further polarized the public debate. She also discusses how Bergson and Einstein, toward the end of their lives, each reflected on his rival’s legacy—Bergson during the Nazi occupation of Paris and Einstein in the context of the first hydrogen bomb explosion. The Physicist and the Philosopher is a magisterial and revealing account that shows how scientific truth was placed on trial in a divided century marked by a new sense of time.

The Poetic Structure of the World

The Poetic Structure of the World
Author: Fernand Hallyn
Publisher:
Total Pages: 374
Release: 1990
Genre: Philosophy
ISBN:

The Poetic Structure of the World is a major reconsideration of a crucial turning point in Western thought and culture: the heliocentric revolution of Copernicus and Kepler. Conceiving of their work not in terms of a history of science or astronomy, but as events embedded in a wider field of images, symbols, texts, and practices, Fernand Hallyn insists that these new representations of the universe cannot be explained by recourse to theories of "genius" and "intuition." The scientific imagination is not fundamentally different from a mythic or poetic imagination, and the work of Copernicus and Kepler, Hallyn contends, must be examined on the level of rhetorical structure. Thus the new sun-centered universe is shown to be inseparable from the aesthetic, epistemological, theological, and social imperatives of both Neoplatonism and Mannerism in the sixteenth century.