The culture of algae and its applications

An article explaining how the methods and results from the time spent by the author culturing algae can be applied to other algal investigations. The work by the author found that physiological requirements differ widely among algae belonging to different systematic groups. Details are given of the results of a series of experiments which were undertaken in solutions with similar proporties to some natural waters in the Lake District. Reference is made to a paper under preparation at that time containing data on phytoplankton studied in the field within the Lake District during 1937. Reference is also made to Loch Leven and the affects of bluegreen alga on the number of trout caught weekly during 1937

Photoheliograph alignment system, November 1967 - June 1968

Design and operation of photoheliograph alignment system for use with Apollo telescope moun

Witten effect in a crystalline topological insulator

It has been noted a long time ago that a term of the form theta (e^2/2\pi h) B dot E may be added to the standard Maxwell Lagrangian without modifying the familiar laws of electricity and magnetism. theta is known to particle physicists as the 'axion' field and whether or not it has a nonzero expectation value in vacuum remains a fundamental open question of the Standard Model. A key manifestation of the axion term is the Witten effect: a unit magnetic monopole placed inside a medium with non-zero theta is predicted to bind a (generally fractional) electric charge -e(theta/2 pi+n) with n integer. Here we conduct a first test of the Witten effect, based on the recently established fact that the axion term with theta=pi emerges naturally in the description of the electromagnetic response of a new class of crystalline solids called topological insulators - materials distinguished by strong spin-orbit coupling and non-trivial band structure. Using a simple physical model for a topological insulator, we demonstrate the existence of a fractional charge bound to a monopole by an explicit numerical calculation. We also propose a scheme for generating an 'artificial' magnetic monopole in a topological insulator film, that may be used to facilitate the first experimental test of Witten's prediction.Comment: 7 pages, 2 figures. Version to appear in PRB; minor changes, discussion of several issues expande

Dynamic mechanical analysis and organization/storage of data for polymetric materials

Dynamic mechanical analysis was performed on a variety of temperature resistant polymers and composite resin matrices. Data on glass transition temperatures and degree of cure attained were derived. In addition a laboratory based computer system was installed and data base set up to allow entry of composite data. The laboratory CPU termed TYCHO is based on a DEC PDP 11/44 CPU with a Datatrieve relational data base. The function of TYCHO is integration of chemical laboratory analytical instrumentation and storage of chemical structures for modeling of new polymeric structures and compound

Changes in the phytoplankton

An article discussing changes observed in phytoplankton of the Lake District. An overview is given of previous phytoplankton studies undertaken in the area, detailing some changes found in various waterbodies. Water quality changes in Lake Windermere are mentioned, including the gradual increase of dissolved organic matter (DOM), believed to be caused by the increase of sewage to the lake. The lakes in the Alps are given as an example of a similar anthropogenic pollution scenario. The treatment of a Lake District tarn with bone meal is described. The article goes on to discuss the composition of plankton throughout the year under a variety of climatic conditions. A figure shows seasonal variation in the consistuents of phytoplankton in Windermere (north basin)

Topological Anderson Insulator in Three Dimensions

Disorder, ubiquitously present in solids, is normally detrimental to the stability of ordered states of matter. In this letter we demonstrate that not only is the physics of a strong topological insulator robust to disorder but, remarkably, under certain conditions disorder can become fundamentally responsible for its existence. We show that disorder, when sufficiently strong, can transform an ordinary metal with strong spin-orbit coupling into a strong topological `Anderson' insulator, a new topological phase of quantum matter in three dimensions.Comment: 5 pages, 2 figures. For related work and info visit http://www.physics.ubc.ca/~franz

Guidelines for Teaching Object Orientation with Java

How to best teach object orientation to first year students is currently a topic of much debate. One of the tools suggested to aid in this task is BlueJ, an integrated development environment specifically designed for teaching. BlueJ supports a unique style of introduction of OO concepts. In this paper we discuss a set of problems with OO teaching, present some guidelines for better course design and show how BlueJ can be used to make significant improvements to introductory OO courses. We end by esenting a description of a possible project sequence using this teaching approach