Extraction Methods and an Investigation of Drosophila Lipids

In earlier work (8) we extracted lipids from dried, macerated Drosophila melanogaster with ether, but later, working with larger quantities of undried flies, we found that most of the phospholipids were autolyzed. Kates' studies (2) led him to suggest n-propanol or isopropanol for lipid extraction (isopropanol was his later choice (6, 7)). Attempting to meet the requirements discussed above, we developed a new and relatively simple method of extraction employing n-propanol (9), or chloroformmethanol (2:1). The latter proved to be a more useful solvent. The method will be described in detail below, with results of an examination of Drosophila lipids

Double power series method for approximating cosmological perturbations

We introduce a double power series method for finding approximate analytical solutions for systems of differential equations commonly found in cosmological perturbation theory. The method was set out, in a non-cosmological context, by Feshchenko, Shkil' and Nikolenko (FSN) in 1966, and is applicable to cases where perturbations are on sub-horizon scales. The FSN method is essentially an extension of the well known Wentzel-Kramers-Brillouin (WKB) method for finding approximate analytical solutions for ordinary differential equations. The FSN method we use is applicable well beyond perturbation theory to solve systems of ordinary differential equations, linear in the derivatives, that also depend on a small parameter, which here we take to be related to the inverse wave-number. We use the FSN method to find new approximate oscillating solutions in linear order cosmological perturbation theory for a flat radiation-matter universe. Together with this model's well known growing and decaying M\'esz\'aros solutions, these oscillating modes provide a complete set of sub-horizon approximations for the metric potential, radiation and matter perturbations. Comparison with numerical solutions of the perturbation equations shows that our approximations can be made accurate to within a typical error of 1%, or better. We also set out a heuristic method for error estimation. A Mathematica notebook which implements the double power series method is made available online.Comment: 22 pages, 10 figures, 2 tables. Mathematica notebook available from Github at https://github.com/AndrewWren/Double-power-series.gi

Phospholipides containing amino acids other than serine. I. Detection

In view of the widespread occurrence of the amino acid-containing lipides and the unique course of their metabolism during development of Drosophila, we have carried out extensive investigations concerned with their isolation and chemical nature. The present report is concerned primarily with techniques and procedures developed to insure removal of non-lipide contaminants from preparations of these lipides

Inventing Leadership: The Challenge of Democracy

The tension between ruler and ruled in democratic societies has never been satisfactorily resolved, and the competing interpretations of this relationship lie at the bottom of much modern political discourse. In this fascinating book, Thomas Wren clarifies and elevates the debates over leadership by identifying the fundamental premises and assumptions that underlie past and present understandings.https://scholarship.richmond.edu/bookshelf/1022/thumbnail.jp

The Historical and Contemporary Contexts of Leadership: A Conceptual Model

Stating that leadership is a complex phenomenon repeats a truism that is painfully obvious to all who have ever participated in, observed, or analyzed the process as leaders, followers, students or scholars. Despite its inherent complexity, those who seek an understanding of the nature of leadership and leadership processes are well rewarded by the insights generated thereby. This essay provides an expanded conception of one of the key elements of the leadership process--the context of leadership

The Leader\u27s Companion: Insights on Leadership Through the Ages

This book serves as a guided introduction to the rich a diverse perspectives on leadership throughout the ages and throughout the world. Each of the selections, introduced by the editor, presents enlightening thoughts on a different aspect of leadership. Writings by Plato, Aristotle, Lao-tzu and others demonstrate that the challenges of leadership are as old as civilization. Machiavelli, Tolstoy, Ghandi, and W.E.B. Du Bois provide a wide range of insights into the eternal practice and problems of leadership. Modern masters of leadership such as James MacGregor Burns, John Kotter, and Warren Bennis join such leading practitioners as Max De Pree and Roger B. Smith in discussing contemporary issues in leadership theory and practice.https://scholarship.richmond.edu/bookshelf/1019/thumbnail.jp